CenterState Bank (CSFL) 10-K 28 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Feb. 26, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Entity Registrant Name	CenterState Bank Corporation
Trading Symbol	CSFL
Entity Central Index Key	1,102,266
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		95,803,337
Entity Public Float			$ 1,959,167

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 107,007	$ 68,571
Deposits in other financial institutions (restricted cash)	28,345	16,991
Federal funds sold and FRB deposits	231,981	195,057
Cash and cash equivalents	367,333	280,619
Trading securities, at fair value	1,737	6,777
Available for sale debt securities, at fair value	1,727,348	1,060,143
Held to maturity debt securities (fair value of $212,179 and $231,615at December 31, 2018 and 2017, respectively)	216,833	232,399
Loans held for sale (see Note 4)	40,399	19,647
Loans, excluding purchased credit impaired	8,181,533	4,609,063
Purchased credit impaired loans	158,971	164,158
Allowance for loan losses	(39,770)	(32,825)
Net Loans	8,300,734	4,740,396
Bank premises and equipment, net	227,454	141,886
Accrued interest receivable	33,143	18,628
FHLB, FRB and other stock, at cost	79,584	34,876
Goodwill	802,880	257,683
Core deposit intangible, net	66,225	24,063
Other intangible assets, net	2,953	551
Bank owned life insurance	267,820	146,739
Other repossessed real estate owned	2,909	3,987
Deferred income tax asset, net	51,462	37,725
Bank property held for sale	25,080	11,354
Interest rate swap derivatives, at fair value	92,475	42,480
Prepaid expense and other assets	31,219	64,022
TOTAL ASSETS	12,337,588	7,123,975
Deposits:
Demand - non-interest bearing	2,923,640	1,999,901
Demand - interest bearing	1,811,006	1,058,985
Savings and money market accounts	2,920,730	1,668,954
Time deposits	1,821,960	832,683
Total deposits	9,477,336	5,560,523
Securities sold under agreement to repurchase	57,772	52,080
Federal funds purchased	294,360	331,490
Other borrowed funds	361,000	175,000
Corporate debentures	32,415	26,192
Accrued interest payable	2,627	1,169
Interest rate swap derivatives, at fair value	92,892	43,259
Payables and accrued expenses	47,842	29,512
Total liabilities	10,366,244	6,219,225
Stockholders' equity:
Common stock, $.01 par vlue: 200,000,000 shares authorized; 95,679,596 and 60,161.334 shares issued and outstanding at December 31,2018 and 2017, respectively	957	602
Additional paid-in capital	1,699,031	737,905
Retained earnings	293,777	173,248
Accumulated other comprehensive loss	(22,421)	(7,005)
Total stockholders' equity	1,971,344	904,750
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 12,337,588	$ 7,123,975

CONSOLIDATED BALANCE SHEETS(Par

CONSOLIDATED BALANCE SHEETS(Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Held-to-maturity securities, fair value	$ 212,179	$ 231,615
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	95,679,596	60,161,334
Common stock, shares outstanding	95,679,596	60,161,334

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Loans		$ 405,881	$ 219,972	$ 163,625
Investment securities:
Taxable		42,723	22,598	18,920
Tax-exempt		6,399	5,324	3,909
Federal funds sold and other		5,629	3,432	2,211
Total interest income		460,632	251,326	188,665
Interest expense:
Deposits		33,260	11,079	6,934
Securities sold under agreement to repurchase		632	246	103
Federal funds purchased and other borrowings		11,445	3,108	1,154
Corporate debentures		2,213	1,350	1,149
Total interest expense		47,550	15,783	9,340
Net interest income		413,082	235,543	179,325
Provision for loan losses		8,283	4,958	4,962
Net interest income after loan loss provision		404,799	230,585	174,363
Non-interest income:
Correspondent banking capital markets revenue		28,884	23,520	28,817
Other correspondent banking related revenue		4,504	4,821	4,868
Small business administration loans revenue		3,532	775	150
Debit, prepaid, ATM and merchant card related fees		16,243	9,035	8,254
Wealth management related revenue		2,657	3,554	3,237
FDIC indemnification income				96
FDIC indemnification asset amortization		0	0	(1,166)
Bank owned life insurance income		5,976	3,293	2,534
Gain on sale of deposits		611
Gain on sale of trust department			1,224
Net (loss) gain on sale of debt securities available for sale		(22)	(7)	13
Other non-interest income		7,301	2,463	3,169
Total other income		105,127	65,175	64,369
Non-interest expense:
Salaries, wages and employee benefits		172,318	109,412	90,881
Occupancy expense		20,897	12,777	9,805
Depreciation of premises and equipment		9,788	7,247	6,373
Supplies, stationary and printing		2,498	1,610	1,340
Marketing expenses		6,235	3,929	3,125
Data processing expense		14,308	8,436	6,867
Legal, audit and other professional fees		6,163	3,644	3,657
Amortization of intangibles		10,018	4,066	3,074
Postage and delivery		2,961	1,938	1,684
ATM, debit and merchant card related expenses		4,253	2,746	2,850
Bank regulatory expenses		4,885	3,051	3,420
Gain on sale of repossessed real estate (“OREO”)		(1,933)	(876)	(1,528)
Valuation write down of repossessed real estate (“OREO”)		482	682	871
Loss (gain) on repossessed assets other than real estate		138	(23)	46
Foreclosure related expenses		2,815	2,252	2,392
Merger related expenses		34,912	13,046	11,444
Impairment on bank property held for sale		2,667	519	1,150
Loss on termination of FDIC loss share agreements		0	0	17,560
Other expenses		19,062	12,029	9,470
Total other expenses		312,467	186,485	174,481
Income before provision for income taxes		197,459	109,275	64,251
Provision for income taxes		41,024	53,480	21,910
Net income		156,435	55,795	42,341
Other comprehensive (loss) gain income, net of tax:
Unrealized available for sale debt securities holding (loss) gain, net ofincome taxes of ($5,233), $1,765 and ($6,288), respectively		(15,432)	2,806	(10,004)
Less: reclassified adjustments for (loss) gain included in net income, net of income tax (benefit) expense of ($6), ($3) and $5, respectively		16	4	(8)
Net unrealized (loss) gain on available for sale debt securities, net of income taxes		(15,416)	2,810	(10,012)
Total comprehensive income		$ 141,019	$ 58,605	$ 32,329
Earnings per share:
Basic		$ 1.78	$ 0.97	$ 0.89
Diluted		$ 1.76	$ 0.95	$ 0.88
Common shares used in the calculation of earnings per share:
Basic	[1]	87,641,220	57,244,698	47,409,142
Diluted	[1]	88,758,853	58,340,813	48,191,523
Mortgage Banking Income
Non-interest income:
Non interest income		$ 12,610	$ 1,511	$ 833
Service Charges on Deposit Accounts
Non-interest income:
Non interest income		$ 22,831	$ 14,986	$ 13,564
[1]	Excludes participating securities.

CONSOLIDATED STATEMENTS OF IN_2

CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Unrealized available for sale debt securities holding (loss) gain, income taxes	$ (5,233)	$ 1,765	$ (6,288)
Reclassifications of loss included in net income, income taxes	$ (6)	$ (3)	$ 5

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	HCBF Holding Company, Inc. [Member]	Sunshine Company [Member]	Gateway Financial Holdings Of Florida Inc [Member]	Community Bank Of South Florida Inc [Member]	Platinum Bank Holding Company [Member]	Charter Financial Corporation [Member]	Common Stock [Member]	Common Stock [Member]HCBF Holding Company, Inc. [Member]	Common Stock [Member]Sunshine Company [Member]	Common Stock [Member]Gateway Financial Holdings Of Florida Inc [Member]	Common Stock [Member]Community Bank Of South Florida Inc [Member]	Common Stock [Member]Platinum Bank Holding Company [Member]	Common Stock [Member]Charter Financial Corporation [Member]	Additional Paid in Capital [Member]	Additional Paid in Capital [Member]HCBF Holding Company, Inc. [Member]	Additional Paid in Capital [Member]Sunshine Company [Member]	Additional Paid in Capital [Member]Gateway Financial Holdings Of Florida Inc [Member]	Additional Paid in Capital [Member]Community Bank Of South Florida Inc [Member]	Additional Paid in Capital [Member]Platinum Bank Holding Company [Member]	Additional Paid in Capital [Member]Charter Financial Corporation [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balances at beginning at Dec. 31, 2015	$ 490,514							$ 455							$ 393,191							$ 95,430	$ 1,438
Balances at beginning, shares at Dec. 31, 2015								45,459,195
Net income	42,341																					42,341
Unrealized holding loss on available for sale debt securities,	(10,012)																						(10,012)
Dividends paid - common	(7,681)																					(7,681)
Stock grants issued	200							$ 2							198
Stock grants issued, shares								232,489
Stock based compensation expense	4,423														4,423
Stock options exercised	$ 1,769							$ 3							1,766
Stock options exercised, Shares	229,583							229,583
Stock repurchase	$ (962)							$ (1)							(961)
Stock repurchase, shares								(50,328)
Stock issued pursuant to acquisition					$ 31,865							$ 23							$ 31,842
Stock issued pursuant to acquisition, shares												2,276,042
Balances at ending at Dec. 31, 2016	552,457							$ 482							430,459							130,090	(8,574)
Balances at ending, shares at Dec. 31, 2016								48,146,981
Net income	55,795																					55,795
Unrealized holding loss on available for sale debt securities,	2,810																						2,810
Reclassification of the disproportionate tax effect on unrealized losses on available for sale securities resulting from the change in federal tax rate																						1,241	(1,241)
Dividends paid - common	(13,878)																					(13,878)
Stock grants issued	403							$ 2							401
Stock grants issued, shares								242,854
Stock based compensation expense	4,586														4,586
Stock options exercised	$ 6,715							$ 6							6,709
Stock options exercised, Shares	598,039							598,039
Stock repurchase	$ (1,131)							$ (1)							(1,130)
Stock repurchase, shares								(45,236)
Stock issued pursuant to acquisition				$ 107,087		$ 110,833					$ 43		$ 43					$ 107,044		$ 110,790
Stock issued pursuant to acquisition, shares											4,244,441		4,279,255
Stock options acquired and converted pursuant to Gateway acquisition				$ 15,811														$ 15,811
Stock issued pursuant to public offering, net of costs of $529	63,262							$ 27							63,235
Stock issued pursuant to public offering, net of costs, shares								2,695,000
Balances at ending at Dec. 31, 2017	$ 904,750							$ 602							737,905							173,248	(7,005)
Balances at ending, shares at Dec. 31, 2017	60,161,334							60,161,334
Net income	$ 156,435																					156,435
Unrealized holding loss on available for sale debt securities,	(15,416)																						(15,416)
Dividends paid - common	(35,906)																					(35,906)
Stock grants issued	650							$ 3							647
Stock grants issued, shares								236,921
Stock based compensation expense	4,193														4,193
Stock options exercised	$ 14,707							$ 18							14,689
Stock options exercised, Shares	1,793,339							1,793,339
Stock repurchase	$ (1,027)							$ (1)							(1,026)
Stock repurchase, shares								(38,496)
Stock issued pursuant to acquisition		$ 387,279	$ 181,413				$ 349,809		$ 151	$ 70				$ 114		$ 387,128	$ 181,343				$ 349,695
Stock issued pursuant to acquisition, shares									15,051,639	7,050,645				11,424,214
Stock options acquired and converted pursuant to Gateway acquisition		$ 18,025	$ 6,432													$ 18,025	$ 6,432
Balances at ending at Dec. 31, 2018	$ 1,971,344							$ 957							$ 1,699,031							$ 293,777	$ (22,421)
Balances at ending, shares at Dec. 31, 2018	95,679,596							95,679,596

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unrealized holding gain (loss) on available for sale securities, deferred income tax	$ (5,233)	$ 1,765	$ (6,288)
Accumulated Other Comprehensive Income (Loss) [Member]
Unrealized holding gain (loss) on available for sale securities, deferred income tax	$ 5,233	$ 1,765	$ 6,288
Retained Earnings [Member]
Dividends paid - common, per share	$ 0.40	$ 0.24	$ 0.16
Additional Paid in Capital [Member]
Public Offering Costs		$ 529

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 156,435	$ 55,795	$ 42,341
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	8,283	4,958	4,962
Depreciation of premises and equipment	9,788	7,247	6,373
Accretion of purchase accounting adjustments	(51,131)	(34,264)	(37,972)
Net amortization of investment securities	12,449	9,954	11,509
Net deferred loan origination fees	1,873	345	(398)
Net loss (gain) on sale of available for sale debt securities	22	7	(13)
Trading securities revenue	(57)	(242)	(519)
Purchases of trading securities	(254,555)	(230,074)	(186,150)
Proceeds from sale of trading securities	259,652	235,922	176,393
Repossessed real estate owned valuation write down	482	682	871
Gain on sale of repossessed real estate owned	(1,933)	(876)	(1,528)
Loss (gain) on repossessed assets other than real estate	138	(23)	46
Gain on extinguishment of debt	0	0	(308)
Gain on sale of residential loans held for sale	(10,803)	(1,511)	(833)
Residential loans originated and held for sale	(403,492)	(93,642)	(39,748)
Proceeds from sale of residential loans held for sale	403,583	77,791	40,557
Change in fair value of residential loans held for sale	(1,081)
(Gain) loss on disposal of and or sale of fixed assets	(762)	(225)	1
Gain on disposal of bank property held for sale	(2,675)	(340)	(797)
Impairment on bank property held for sale	2,667	519	1,150
Gain on sale of small business administration loans	(3,532)	(775)	(150)
Small business administration loans originated for sale	(35,693)	(12,268)	(2,672)
Proceeds from sale of small business administration loans	39,225	13,043	2,822
Gain on sale of deposits	(611)
Gain on sale of trust department		(1,224)
Deferred income taxes	21,511	31,192	3,647
Tax deduction in excess of book deduction for stock awards	(6,149)	(3,007)
Stock based compensation expense	4,193	4,586	4,423
Bank owned life insurance income	(5,976)	(3,293)	(2,534)
FDIC indemnification asset amortization	0	0	1,166
Loss from termination of FDIC loss share agreements	0	0	17,560
Net cash from changes in:
Net changes in accrued interest receivable, prepaid expenses, and other assets	61,575	(48,145)	(3,585)
Net change in accrued interest payable, accrued expense, and other liabilities	(9,988)	10,625	131
Net cash provided by operating activities	193,438	22,757	36,745
Cash flows from investing activities:
Purchases of investment securities	(40,788)	(56,673)	(10,054)
Purchases of mortgage backed securities	(539,807)	(444,146)	(294,209)
Proceeds from pay-downs of mortgage backed securities	217,862	123,917	130,773
Proceeds from sales of investment securities	58,768	104,260	79,657
Proceeds from sales of mortgage backed securities	296,884	208,432	62,418
Proceeds from called investment securities	1,210	865	10,890
Proceeds from maturities of investment securities	61,000	1,000	615
Purchases of investment securities	0	(2,693)	(71,316)
Purchases of mortgage backed securities	0	(1,695)	(3,730)
Proceeds from called investment securities	0	0	57,760
Proceeds from pay-downs of mortgage backed securities	14,232	20,874	37,449
Purchases of FHLB, FRB and other stock	(67,115)	(15,919)	(666)
Proceeds from sales of FHLB, FRB and other stock	36,244	5,572	29
Net increase in loans	(363,401)	(286,110)	(287,901)
Cash received from FDIC loss sharing agreements	0	0	5,482
Purchase of bank owned life insurance	0	(30,000)	(10,000)
Purchases of premises and equipment, net	(24,025)	(10,289)	(6,683)
Proceeds from sale of repossessed real estate	12,591	6,811	18,008
Proceeds from sale of premises and equipment, net	2,661	556
Proceeds from sale of bank property held for sale	16,001	7,437	4,340
Net cash from bank acquisitions	229,689	86,530	41,885
Net cash used in investing activities	(87,994)	(281,271)	(235,253)
Cash flows from financing activities:
Net increase in deposits	97,083	180,744	232,467
Sale of deposits	25,341
Net increase in securities sold under agreement to repurchase	5,339	18,084	411
Net (decrease) increase in federal funds purchased	(37,130)	69,504	61,736
Net (decrease) increase in other borrowings	(77,920)	40,268	(57,418)
Extinguishment of debt	0	0	(8,680)
Net (decrease) increase in payable to shareholders for acquisitions	(217)	(89)	38
Termination of corporate debentures	(9,000)
Stock options exercised	14,707	6,715	1,769
Proceeds from stock offering, net of offering costs	0	63,262	0
Stock repurchased	(1,027)	(1,131)	(962)
Dividends paid	(35,906)	(13,878)	(7,681)
Net cash (used in) provided by financing activities	(18,730)	363,479	221,680
Net increase in cash and cash equivalents	86,714	104,965	23,172
Cash and cash equivalents, beginning of period	280,619	175,654	152,482
Cash and cash equivalents, end of period	367,333	280,619	175,654
Supplemental noncash disclosures:
Transfer of loans to other real estate owned	4,661	3,108	7,959
Transfers of bank property to held for sale	4,302	4,534	4,936
Cash paid during the period for:
Interest	48,450	17,493	8,920
Income taxes	$ 16,624	$ 17,818	$ 20,519

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	(1) Summary of Significant Accounting Policies (a) Nature of operations and principles of consolidation The Consolidated Financial Statements of CenterState Bank Corporation (the “Company”) include the accounts of the Company, and its wholly owned subsidiaries CenterState Bank, N.A., R4ALL, Inc. and CSFL Insurance Corp. All significant intercompany accounts and transactions have been eliminated in consolidation. At December 31, 2018, the Company, through its subsidiary bank, operated as a community bank headquartered in the state of Florida, providing traditional retail, commercial, mortgage, wealth management and SBA services throughout its Florida, Georgia and Alabama branch network and customer relationships in neighboring states. The Company’s primary deposit products are checking, savings and term certificate accounts, and its primary lending products include commercial real estate loans, residential real estate loans, commercial loans and consumer loans. Substantially all loans are secured by commercial real estate, residential real estate, business assets or consumer assets. There are no significant concentrations of loans to any one industry or customer. However, the customers’ ability to repay their loans is dependent on the real estate and general economic conditions in the area. The Company also provides correspondent banking and capital markets services to over 600 community banks nationwide. R4ALL, Inc. is a non bank subsidiary incorporated during the third quarter of 2009. The primary purpose of this subsidiary is to purchase, hold, and dispose of troubled assets acquired from the Company’s subsidiary bank. CSFL Insurance Corp. is a non bank subsidiary incorporated during the fourth quarter of 2015. The primary purpose of this subsidiary is to function as a captive insurance subsidiary pursuant to Section 831(b) of the U.S. Tax Code. The following is a description of the basis of presentation and the significant accounting and reporting policies, which the Company follows in preparing and presenting its Consolidated Financial Statements. (b) Use of estimates To prepare financial statements in conformity with U.S. generally accepted accounting principles, management makes estimates and assumptions based on available information. These estimates and assumptions affect the amounts reported in the financial statements and the disclosures provided. Significant items subject to estimates and assumptions include allowance for loan losses, fair values of financial instruments, useful life of intangibles and valuation of goodwill, fair value estimates of stock-based compensation, fair value estimates of OREO, and deferred tax assets. Actual results could differ from these estimates. (c) Cash flow reporting For purposes of the statement of cash flows, the Company considers cash and due from banks, federal funds sold, money market and non-interest bearing deposits in other banks with a purchased maturity of three months or less to be cash equivalents. Net cash flows are reported for customer loan and deposit transactions, interest bearing deposits in other financial institutions, federal funds purchased, repurchase agreements, proceeds from capital offering and other borrowed funds. (d) Interest bearing deposits in other financial institutions Interest bearing deposits in other financial institutions mature within one year and are carried at cost and are included in Cash and Due From Banks in the Consolidated Balance Sheets. (e) The Company engages in trading activities for its own account. Securities that are held principally for resale in the near term are recorded at fair value with changes in fair value included in earnings. Interest is included in net interest income. (f) Investment Debt Securities Debt securities are classified as held to maturity and carried at amortized cost when management has the positive intent and ability to hold them to maturity. Debt securities not classified as held to maturity or trading are classified as available for sale. Debt s ecurities available for sale are carried at fair value, with unrealized holding gains and losses reported in other comprehensive income, net of tax. Interest income includes amortization of purchase premium or discount. Premiums on securities are amortized to the earliest call date. Discounts on securities are amortized on the level-yield method without anticipating prepayments, except for mortgage backed securities where prepayments are anticipated. Gains and losses on sales are recorded on the trade date and determined using the specific identification method. Securities are evaluated for other-than-temporary impairment (“OTTI”) on at least an annual basis, and more frequently when economic or market conditions warrant such an evaluation. For securities in an unrealized loss position, management considers the extent and duration of the unrealized loss, and the financial condition and near-term prospects of the issuer. Management also assesses whether it intends to sell, or it is more likely than not that it will be required to sell, a security in an unrealized loss position before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the entire difference between amortized cost and fair value is recognized as impairment through earnings. For debt securities that do not meet the aforementioned criteria, the amount of impairment is split into two components as follows: 1) OTTI related to credit loss, which must be recognized in the income statement; and 2) other-than-temporary impairment related to other factors, which is recognized in other comprehensive income. The credit loss is defined as the difference between the present value of the cash flows expected to be collected and the amortized cost basis. (g) Bond commissions revenue recognition Bond sales transactions and related revenue and expenses are recorded on a settlement date basis. The effect on the financial statements of using the settlement date basis rather than the trade date basis is not material. (h) Loans held for sale Effective January 1, 2018, mortgage loans originated and intended for sale in the secondary market are carried at fair value with changes in fair value recognized in current period earning. For periods prior to December 31, 2018, mortgage loans held for sale were carried at the lower of aggregate cost or fair value, as determined by outstanding commitments from investors. Net unrealized losses, if any, are recorded as a valuation allowance and charged to earnings. Mortgage loans held for sale are generally sold with servicing rights released. Gains and losses on sales of mortgage loans are based on the difference between the selling price and the carrying value of the related loan sold. (i) Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at their outstanding unpaid principal balance net of purchase premiums and discounts, deferred loan fees and costs, and an allowance for loan losses. Interest income is accrued on the unpaid principal balance. The recorded investment in a loan excludes accrued interest receivable, deferred fees, and deferred costs because they are not considered material. A loan is considered a troubled debt restructured loan based on individual facts and circumstances. A modification may include either an increase or reduction in interest rate or deferral of principal payments or both. Loans for which the terms have been modified resulting in a concession, and for which the borrower is experiencing financial difficulties, are considered troubled debt restructurings. The Company classifies troubled debt restructured loans as impaired and evaluates the need for an allowance for loan losses on a loan-by-loan basis. An allowance for loan losses is based on either the present value of estimated future cash flows or the estimated fair value of the underlying collateral. Loans retain their accruing or non-accruing status at the time of modification. Loan origination fees and the incremental direct cost of loan origination, are deferred and recognized in interest income without anticipating prepayments over the contractual life of the loans. If the loan is prepaid, the remaining unamortized fees and costs are charged or credited to interest income. Amortization ceases for non-accrual loans. A loan is moved to non-accrual status in accordance with the Company’s policy typically after 90 days of non-payment, or less than 90 days of non-payment if management determines that the full timely collection of principal and interest becomes doubtful. Past due status is based on the contractual terms of the loan. In all cases, loans are placed on non-accrual or charged-off at an earlier date if collection of principal or interest is considered doubtful. Non-accrual loans and loans past due 90 days still on accrual include both smaller balance homogeneous loans that are collectively evaluated for impairment and individually classified impaired loans. Single family home loans, consumer loans and smaller commercial, land, development and construction loans (less than $ 500 ) are monitored by payment history, and as such, past due payments is generally the triggering mechanism to determine non - accrual status. Larger (greater than $ 500 ) commercial, land, development and construction loans are monitored on a loan level basis, and therefore in these cases it is more likely that a loan may be placed on non - accrual status before it becomes 90 days past due. All interest accrued but not received for loans placed on non-accrual is reversed against interest income. Interest received on such loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured. Non real estate consumer loans are typically charged off no later than 120 days past due. The Company, considering current information and events regarding the borrower’s ability to repay their obligations, considers a loan to be impaired when it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement. When a loan is considered to be impaired, the amount of the impairment is measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, the secondary market value of the loan, or the fair value of the collateral for collateral dependent loans. Interest income on impaired loans is recognized in accordance with the Company’s non-accrual policy. Impaired loans are written down to the extent that principal is judged to be uncollectible and, in the case of impaired collateral dependent loans where repayment is expected to be provided solely by the underlying collateral and there is no other available and reliable sources of repayment, are written down to the lower of cost or collateral value less estimated selling costs. Impairment losses are included in the allowance for loan losses. Large groups of smaller balance homogeneous loans, such as consumer and residential real estate loans, are collectively evaluated for impairment, and accordingly, they are not separately identified for impairment disclosures. (j) Purchased credit-impaired loans As a part of business acquisitions, the Company acquires loans, some of which have shown evidence of credit deterioration since origination. These purchased credit-impaired (“PCI”) loans were determined to be credit impaired based on specific risk characteristics of the loan, including, but not limited to loans on non-accrual status, loans with insufficient cash flow, past due loans, high loan-to-value ratios, loans in process of foreclosure, or any TDR with loss potential. The Company, as a purchaser, is permitted to aggregate credit impaired loans acquired in the same fiscal quarter into one or more pools, provided that the loans have common risk characteristics. A pool is then accounted for as a single asset with a single composite interest rate and an aggregate expectation of cash flows. For the loan portfolios acquired, the Company aggregated the commercial, consumer, and residential loans into pools of loans with common risk characteristics for each institution acquired. These acquired loans were recorded at the acquisition date fair value, and after acquisition, losses are recognized through the allowance for loan losses. The Company estimates the amount and timing of expected cash flows for each acquired loan pool and the expected cash flows in excess of the amount paid is recorded as interest income over the remaining life of the loan pools. As frequently as quarter or as long as annually, the Company updates the amount of loan principal and interest cash flows expected to be collected, incorporating assumptions regarding default rates, loss severities, the amounts and timing of prepayments and other factors that are reflective of current market conditions. Probable decreases in expected loan principal cash flows trigger the recognition of impairment, which is measured as the present value of the expected principal loss plus any related foregone interest cash flows discounted at the pool’s effective interest rate. Impairments that occur after the acquisition date are recognized through provision for loan losses. Probable and significant increases in expected principal cash flows would first reverse any previously recorded allowance for loan losses; any remaining increases are recognized prospectively as interest income over the life of the pool. The impacts of (i) prepayments, (ii) changes in variable interest rates, and (iii) any other changes in the timing of expected cash flows are recognized prospectively as adjustments to interest income over the life of the pool. Disposals of loans, which may include sales of loans, receipt of payments in full by the borrower, or foreclosure, result in removal of the loan from the purchased credit impaired portfolio. (k) Concentration of credit risk Most of the Company’s business activity is with customers located within Southeastern United States largely in Florida, also in Alabama and Georgia. Therefore, the Company’s exposure to credit risk is significantly affected by changes in the economy and the real estate market within Southeast, primarily in Florida. (l) Allowance for loan losses The allowance for loan losses is a valuation allowance for probable incurred credit losses. Loan losses are charged against the allowance when management believes the uncollectibility of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance. Management estimates the allowance balance required using past loan loss experience, the nature and volume of the portfolio, information about specific borrower situations and estimated collateral values, economic conditions, and other factors. Allocations of the allowance may be made for specific loans, but the entire allowance is available for any loan that, in management’s judgment, should be charged-off. The allowance consists of specific and general components. The specific component relates to loans that are individually classified as impaired. The general component covers loans that are not individually classified as impaired and is based on historical loss experience adjusted for current factors. A loan is impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement. Loans, for which the terms have been modified resulting in a concession, and for which the borrower is experiencing financial difficulties, are considered troubled debt restructurings and classified as impaired. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. If a loan is impaired, a portion of the allowance is allocated so that the loan is reported, net, at the present value of estimated future cash flows using the loan’s existing rate or at the fair value of collateral if repayment is expected solely from the collateral. Commercial, commercial real estate, land, acquisition and development, and construction loans over $500 are individually evaluated for impairment. Large groups of smaller balance homogeneous loans, such as consumer and residential real estate loans, are collectively evaluated for impairment, and accordingly, they are not separately identified for impairment disclosures. Troubled debt restructurings are separately identified for impairment disclosures and are measured at the present value of estimated future cash flows using the loan’s effective rate. If a troubled debt restructuring is considered to be a collateral dependent loan, the loan is reported, net, at the fair value of the collateral. For troubled debt restructurings that subsequently default, the Company determines the amount of reserve in accordance with the accounting policy for the allowance for loan losses. The general component covers non-impaired loans and is based on historical loss experience adjusted for current factors. The historical loss experience is determined by portfolio segment and is based on the actual loss history experienced by the Company over the most recent two years. The portfolio segments identified by the Company are residential loans, commercial real estate loans, construction and land development loans, commercial and industrial and consumer and other. This actual loss experience is supplemented with other economic factors based on the risks present for each portfolio segment. These economic factors include consideration of the following: levels of and trends in delinquencies and impaired loans; volume and severity of adversely classified or graded loans; levels of and trends in charge-offs and recoveries; trends in volume and terms of loans; effects of any changes in risk selection and underwriting standards; other changes in lending policies, procedures, and practices; experience, ability, and depth of lending management and other relevant staff; national and local economic trends and conditions; industry conditions; and effects of changes in credit concentrations. The Company segregates and evaluates its loan portfolio through the five portfolio segments: residential real estate, commercial real estate, land/ land development/construction, commercial and consumer/other. Residential real estate loans are a mixture of fixed rate and adjustable rate residential mortgage loans, including first mortgages, second mortgages or home equity lines of credit. As a policy, the Company holds adjustable rate loans and sells a portion of its fixed rate loan originations into the secondary market. Changes in interest rates or market conditions may impact a borrower’s ability to meet contractual principal and interest payments. Residential real estate loans are secured by real property. Commercial real estate loans include loans secured by office buildings, warehouses, retail stores and other property located in or near our markets. These loans are originated based on the borrower’s ability to service the debt and secondarily based on the fair value of the underlying collateral. Land/land development/construction loans include residential and commercial real estate loans and include a mixture of owner occupied and non-owner occupied. The majority of the loans in this category are land related, either undeveloped land, land held for development, residential building lots and commercial building lots. Generally the terms are three to five years, with a potential for renewal at maturity. Commercial loans consist of small-to medium-sized businesses including professional associations, medical services, retail trade, transportation, wholesale trade, manufacturing and tourism. Commercial loans are derived from our market areas and underwritten based on the borrower’s ability to service debt from the business’s underlying cash flows. As a general practice, we obtain collateral such as inventory, accounts receivable, equipment or other assets although such loans may be uncollateralized but guaranteed. Consumer and other loans include automobiles, boats, mobile homes without land, or uncollateralized but personally guaranteed loans. These loans are originated based primarily on credit scores, debt-to-income ratios and loan-to-value ratios. The Company evaluates the loans acquired from the Gulfstream, First Southern, Community Bank, First National, Platinum and Gateway acquisitions that were not PCI loans as individual loan portfolio segments. The Company considered the levels of and trends in non-performing loans, past-due loans, adverse loan grade classification changes, historical loss rates, environmental factors and impaired loans in arriving at its estimate. The general loan loss allowance recorded for these performing loans acquired from Gulfstream is allocated between the five portfolio segments described above in Note 5. (m) Transfer of financial assets Transfers of financial assets are accounted for as sales, when control over the assets has been relinquished. Control over transferred assets is deemed to be surrendered when the assets have been isolated from the Company, the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity. (n) Other repossessed real estate owned Assets acquired through or instead of loan foreclosure are initially recorded at fair value less costs to sell when acquired, establishing a new cost basis. These assets are subsequently accounted for at lower of cost or fair value less estimated costs to sell. If fair value declines subsequent to foreclosure, a valuation allowance is recorded through expense. Operating costs after acquisition are expensed. Repossessed real estate is included in other repossessed real estate owned and other repossessed assets other than real estate is included in Prepaid Expenses and Other Assets in the Consolidated Balance Sheets. (o) Premises and equipment Land is carried at cost. Premises and equipment are stated at cost less accumulated depreciation. Depreciation is provided on a straight-line basis over the estimated useful lives of the related assets. Buildings are depreciated over a 39 year period, and furniture, fixtures and equipment are depreciated over their related useful life (3 to 15 years). Leasehold improvements are depreciated over the shorter of their useful lives or the term of the lease. Major renewals and betterments of property are capitalized; maintenance, repairs, and minor renewals and betterments are expensed in the period incurred. Upon retirement or other disposition of the asset, the asset cost and related accumulated depreciation are removed from the accounts, and gains or losses are included in income. (p) Software costs Costs of software developed for internal use, such as those related to software licenses, programming, testing, configuration, direct materials and integration, are capitalized and included in premises and equipment. Included in the capitalized costs are those costs related to both our personnel and third party consultants involved in the software development and installation. Once placed in service, the capitalized asset is amortized on a straight-line basis over its estimated useful life, generally three to five years. Capitalized costs of software developed for internal use are reviewed periodically for impairment. (q) Federal Home Loan Bank (FHLB), Federal Reserve Bank (FRB) and other stock The Company’s subsidiary bank is a member of the FHLB and FRB system. Members are required to own a certain amount of stock based on the level of borrowings and other factors, and may invest in additional amounts. FHLB, FRB and other stock is carried at cost, classified as a restricted security, and periodically evaluated for impairment based on ultimate recovery of par value. Both cash and stock dividends are reported as income. (r) Bank owned life insurance (BOLI) The Company, through its subsidiary bank, has purchased life insurance policies on certain key executives or acquired through various bank acquisitions. Bank owned life insurance is recorded at the amount that can be realized under the insurance contract at the balance sheet date, which is the cash surrender value adjusted for other charges or other amounts due that are probable at settlement. (s) Goodwill and other intangible assets Goodwill resulting from business combinations prior to January 1, 2009 represents the excess of the purchase price over the fair value of the net assets of businesses acquired. Goodwill resulting from business combinations after January 1, 2009, is generally determined as the excess of the fair value of the consideration transferred, plus the fair value of any noncontrolling interests in the acquiree, over the fair value of the net assets acquired and liabilities assumed as of the acquisition date. Goodwill and intangible assets acquired in a purchase business combination and determined to have an indefinite useful life are not amortized, but tested for impairment at least annually. The Company has selected November 30 as the date to perform the annual impairment test. Intangible assets with definite useful lives are amortized over their estimated useful lives to their estimated residual values. Goodwill is the only intangible asset with an indefinite life on the Company’s balance sheet. The core deposit intangibles are intangible assets arising from either whole bank acquisitions or branch acquisitions. They are initially measured at fair value and then amortized over a ten-year period on an accelerated basis using the projected decay rates of the underlying core deposits. As a part of normal business operations, the Company originates residential mortgage loans that have been pre-approved by secondary investors. The terms of the loans are set by the secondary investors, and the purchase price that the investor will pay for the loan is agreed to prior to the commitment of the loan by the Company. Generally within three weeks after funding, the loans are transferred to the investor in accordance with the agreed-upon terms. The Company records gains from the sale of these loans on the settlement date of the sale equal to the difference between the proceeds received and the carrying amount of the loan. The gain generally represents the portion of the proceeds attributed to servicing release premiums received from the investors and the realization of origination fees received from borrowers which were deferred as part of the carrying amount of the loan. Between the initial funding of the loans by the Company and the subsequent reimbursement by the investors, the Company carries the loans on its balance sheet at the lower of cost or market. The fair value of the underlying commitment is not material to the Consolidated Financial Statements. The standard structure of mortgage loan sales provides for the Company to retain a portion of the cash flow from the interest payments received on the loan. Fees for servicing loans for investors are based on the outstanding principal balance of the loans serviced and are recognized as income when earned. This cash flow is commonly known as a servicing spread. The servicing spread is recognized as a servicing asset to the extent the spread exceeds adequate compensation for the servicing function and recorded as a component of Other Intangible Assets in the Consolidated Balance Sheets. The fair value of the servicing asset is measured on a recurring basis at the present value of future cash flows using market-based discount assumptions. The future cash flows for each asset are based on their unique characteristics and market-based assumptions for prepayment speeds, default and voluntary prepayments. Adjustments to fair value are recorded as a component of Mortgage Banking Revenue. The value of our servicing portfolio is periodically independently evaluated. (t) FDIC Indemnification Asset The FDIC Indemnification Asset represented the estimated amounts due from the FDIC pursuant to the Loss Share Agreements related to the acquisitions of the three failed banks acquired in 2010, two in 2012 and assumed two additional pursuant to the Company’s 2014 acquisition of First Southern. At acquisition, the FDIC Indemnification Asset represented the discounted value of the FDIC’s reimbursed portion of the estimated losses the Company expects to realize on the loans and other real estate (“Covered Assets”) acquired as a result of the acquisitions. The range of discount rates used on the FDIC Indemnification Asset was 1.21% to 4.53%. As losses were realized on Covered Assets, the portion that the FDIC paid the Company in cash for principal and up to 90 days of interest reduced the FDIC Indemnification Asset. On a quarterly basis, the Company evaluated the FDIC Indemnification Asset to determine if the estimated losses on Covered Assets supported the amount recorded as the FDIC Indemnification Asset. Income accretion was recognized during the loss share period. If the expectation of future losses declined, the income accretion was reduced prospectively over the lesser of the term of the loss share agreement and the estimated remaining life of the Covered Asset. On February 3, 2016, the FDIC bought out the remaining FDIC loss share agreements. As such, the FDIC indemnification asset was written-off effectively accelerating all future FDIC indemnification asset amortization expense as well as ending any future FDIC indemnification income. (u) Loan commitments and related financial instruments Financial instruments include off-balance sheet credit instruments, such as commitments to make loans and commercial letters of credit, issued to meet customer financing needs. The face amount for these items represents the exposure to loss, before considering customer collateral or ability to repay. Such financial instruments are recorded when they are funded. (v) Stock-based compensation Compensation cost is recognized for stock options and restricted stock awards issued to employees, based on the fair value of these awards at the date of grant. A Black-Scholes model is utilized to estimate the fair value of stock options, while the market price of the Company’s common stock at the date of grant is used for restricted stock awards. During 2014 the Company initiated a Long-Term Incentive Plan which included Performance Share Units (“PSUs”). The Monte-Carlo Simulation model was used to estimate fair value of the PSUs at the grant date. Compensation cost is recognized over the required service period, generally defined as the vesting period. (w) Income taxes Income tax expense is the total of the current year income tax due or refundable and the change in deferred tax assets and liabilities. Deferred tax assets and liabilities are the expected future tax amounts for the temporary differences between carrying amounts and tax bases of assets and liabilities, computed using enacted tax rates. A valuation allowance, if needed, reduces deferred tax assets to the amount expected to be realized. A tax position is recognized as a benefit only if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit that is greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded. The Company recognizes interest and/or penalties related to income tax matters in other expenses. On December 22, 2017, the U.S. federal government

Trading Securities

Trading Securities	12 Months Ended
	Dec. 31, 2018
Investments Debt And Equity Securities [Abstract]
Trading Securities	(2) Trading Securities Realized and unrealized gains and losses are included in trading securities revenue, a component of non-interest income. Securities purchased for this portfolio have primarily been municipal securities. A list of the activity in this portfolio for 2018 and 2017 is summarized below. 2018 2017 Beginning balance $ 6,777 $ 12,383 Purchases 254,555 230,074 Proceeds from sales (259,652 ) (235,922 ) Net realized gain on sales 20 195 Mark-to- market adjustment 37 47 Ending balance $ 1,737 $ 6,777

Investment Debt Securities

Investment Debt Securities	12 Months Ended
	Dec. 31, 2018
Investments Debt And Equity Securities [Abstract]
Investment Debt Securities	(3) Investment Debt Securities Available for Sale Debt Securities All of the mortgage backed securities (“MBS”) listed below are residential FNMA, FHLMC, and GNMA MBSs. The fair value of available for sale securities and the related gross unrealized gains and losses recognized in accumulated other comprehensive income (loss) were as follows: December 31, 2018 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value Corporate debt securities $ 6,265 $ 162 $ — $ 6,427 Obligations of U.S. government sponsored entities and agencies 38,794 7 933 37,868 Mortgage backed securities 1,623,906 3,792 33,423 1,594,275 Municipal securities 88,415 698 335 88,778 Total available for sale debt securities $ 1,757,380 $ 4,659 $ 34,691 $ 1,727,348 December 31, 2017 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value U.S. Treasury securities $ 5,000 $ 200 $ — $ 5,200 Obligations of U.S. government sponsored entities and agencies 10,000 — 426 9,574 Mortgage backed securities 982,565 752 10,706 972,611 Municipal securities 71,961 863 66 72,758 Total available for sale debt securities $ 1,069,526 $ 1,815 $ 11,198 $ 1,060,143 The cost of securities sold is determined using the specific identification method. The securities sold during the first quarter of 2018 include some securities acquired through the acquisitions of Sunshine and Harbor on January 1, 2018. These acquired securities were marked to fair value and subsequently sold after the acquisition date, and no gain or loss was recognized from the sale of these securities. Sales of available for sale securities were as follows: 2018 2017 2016 Proceeds $ 355,652 $ 312,692 $ 142,075 Gross gains $ 68 $ 740 $ 13 Gross losses $ 90 $ 747 $ — The tax provisions related to these net realized gains were $(6), $(3) and $5, respectively. Available for sale debt securities pledged at December 31, 2018 and 2017 had a carrying amount (estimated fair value) of $961,721 and $255,788, respectively. These securities were pledged primarily to secure public deposits and repurchase agreements. At year-end 2018 and 2017, there were no holdings of available for sale securities of any one issuer, other than the U.S. Government and its agencies, in an amount greater than 10% of shareholders’ equity. The fair value and amortized cost of available for sale debt securities at year end 2018 by contractual maturity were as follows. Mortgage-backed securities are not due at a single maturity date and are shown separately. Fair Amortized Available for sale debt securities: Value Cost Due in one year or less $ 967 $ 966 Due after one year through five years 6,080 6,038 Due after five years through ten years 30,997 31,396 Due after ten years through thirty years 95,029 95,074 Mortgage backed securities 1,594,275 1,623,906 Total available for sale debt securities $ 1,727,348 $ 1,757,380 The following tables show the Company’s investments’ gross unrealized losses and fair value, aggregated by investment category and length of time the individual securities have been in a continuous unrealized loss position, at December 31, 2018 and 2017. December 31, 2018 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses Obligations of U.S. government sponsored entities and agencies $ 25,104 $ 332 $ 9,398 $ 601 $ 34,502 $ 933 Mortgage backed securities 647,923 10,782 635,172 22,641 1,283,095 33,423 Municipal securities 25,031 316 3,381 19 28,412 335 Total temporarily impaired available for sale debt securities $ 698,058 $ 11,430 $ 647,951 $ 23,261 $ 1,346,009 $ 34,691 December 31, 2017 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses Obligations of U.S. government sponsored entities and agencies $ — $ — $ 9,574 $ 426 $ 9,574 $ 426 Mortgage backed securities 477,925 3,298 316,066 7,408 793,991 10,706 Municipal securities 11,698 66 — — 11,698 66 Total temporarily impaired available for sale debt securities $ 489,623 $ 3,364 $ 325,640 $ 7,834 $ 815,263 $ 11,198 Mortgage-backed securities: At December 31, 2018, nearly 100% of the mortgage-backed securities held by the Company were issued by U.S. government-sponsored entities and agencies, primarily Fannie Mae, Freddie Mac, and Ginnie Mae, institutions which the government has affirmed its commitment to support. Because the decline in fair value is attributable to changes in interest rates and illiquidity, and not credit quality, and because the Company does not have the intent to sell these mortgage-backed securities and it is likely that it will not be required to sell the securities before their anticipated recovery, the Company does not consider these securities to be other-than-temporarily impaired at December 31, 2018. Municipal securities: Unrealized losses on municipal securities have not been recognized into income because the issuers bonds are of high quality, and because management does not intend to sell these investments or more likely than not will not be required to sell these investments before their anticipated recovery. The fair value is expected to recover as the securities approach maturity. Held to Maturity Debt Securities The following reflects the fair value of held to maturity securities and the related gross unrecognized gains and losses as of December 31, 2018 and 2017. December 31, 2018 Gross Gross Amortized Unrecognized Unrecognized Fair Cost Gains Losses Value Mortgage backed securities $ 84,983 $ — $ 2,462 $ 82,521 Municipal securities 131,850 799 2,991 129,658 Total held to maturity debt securities $ 216,833 $ 799 $ 5,453 $ 212,179 December 31, 2017 Gross Gross Amortized Unrecognized Unrecognized Fair Cost Gains Losses Value Mortgage backed securities $ 100,039 $ — $ 1,068 $ 98,971 Municipal securities 132,360 1,781 1,497 132,644 Total held to maturity debt securities $ 232,399 $ 1,781 $ 2,565 $ 231,615 Held to maturity debt securities pledged at December 31, 2018 and 2017 had a carrying amount of $103,710 and $97,389. These securities were pledged primarily to secure public deposits and repurchase agreements. At year-end 2018 and 2017, there were no holdings of held to maturity securities of any one issuer, other than the U.S. Government and its agencies, in an amount greater than 10% of shareholders’ equity. The fair value and amortized cost of held to maturity debt securities at year end 2018 by contractual maturity were as follows. Mortgage-backed securities are not due at a single maturity date and are shown separately. Amortized Held to maturity debt securities Fair Value Cost Due after five years through ten years $ 2,051 $ 2,045 Due after ten years through thirty years 127,607 129,805 Mortgage backed securities 82,521 84,983 Total held to maturity debt securities $ 212,179 $ 216,833 The following tables show the Company’s held to maturity debt investments’ gross unrecognized losses and fair value, aggregated by investment category and length of time the individual securities have been in a continuous unrecognized loss position, at December 31, 2018 and 2017. December 31, 2018 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses Mortgage backed securities $ — $ — $ 82,521 $ 2,462 $ 82,521 $ 2,462 Municipal securities 22,560 203 47,807 2,788 70,367 2,991 Total temporarily impaired held to maturity debt securities $ 22,560 $ 203 $ 130,328 $ 5,250 $ 152,888 $ 5,453 December 31, 2017 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses Mortgage backed securities $ 57,266 $ 451 $ 41,705 $ 617 $ 98,971 $ 1,068 Municipal securities 13,350 186 37,963 1,311 51,313 1,497 Total temporarily impaired held to maturity debt securities $ 70,616 $ 637 $ 79,668 $ 1,928 $ 150,284 $ 2,565 Mortgage-backed securities: At December 31, 2018, 100% of the mortgage-backed securities held by the Company were issued by U.S. government-sponsored entities and agencies, primarily Fannie Mae, Freddie Mac, and Ginnie Mae, institutions which the government has affirmed its commitment to support. Because the decline in fair value is attributable to changes in interest rates and illiquidity, and not credit quality, and because the Company does not have the intent to sell these mortgage-backed securities and it is likely that it will not be required to sell the securities before their anticipated recovery, the Company does not consider these securities to be other-than-temporarily impaired at December 31, 2018. Municipal securities: Unrecognized losses on municipal securities have not been recognized into income because the issuers bonds are of high quality, and because management does not intend to sell these investments or more likely than not will not be required to sell these investments before their anticipated recovery. The fair value is expected to recover as the securities approach maturity.

Loans Held for Sale

Loans Held for Sale	12 Months Ended
	Dec. 31, 2018
Loans Receivable Held For Sale Net [Abstract]
Loans Held for Sale	(4) For periods prior to December 31, 2017, mortgage loans held for sale were valued at the lower of cost or fair value. Effective January 1, 2018, the Company elected to account for these loans under the fair value option with changes in fair value recognized in current period earnings. At the date of funding of the loan, the funded amount of the loan, the relative derivative asset or liability of the associated interest rate lock commitment, less direct costs, becomes the initial recorded investment in the loan held for sale. Such amount approximates the fair value of the loan. This change was accounted for on a prospective basis. Net gains from changes in estimated fair value of mortgage loans held for sale were $1,081 at December 31, 2018. The total unpaid principal balance of loans held for sale was $39,318 at December 31, 2018. No loans held for sale at December 31, 2018 were past due or on non-accrual. The table below summarizes the activity in mortgage loans held for sale for the years ended December 31, 2018 and 2017. December 31, 2018 2017 Beginning balance $ 19,647 $ 2,285 Effect from acquisitions 8,959 — Loans originated 403,492 93,642 Proceeds from sales (403,583 ) (77,791 ) Change in fair value 1,081 — Net realized gain on sales 10,803 1,511 Ending balance $ 40,399 $ 19,647 As loans are closed, they are typically sold at prices specified in the forward contracts. Gains or losses may arise if the yields of the loans delivered vary from those specified in the forward contracts. Derivative mortgage loan commitments, or interest rate locks, are also utilized and relate to the origination of a mortgage that will be held for sale upon funding. The Company began utilizing these derivative financial instruments on its loans held for sale in year 2018 to manage interest rate risk and not for speculative purposes. The changes in fair value of $1,081, the net realized gain on sales of loans held for sale of $10,803, and the net unrealized gain on mortgage banking derivatives of $614 are the main components of Mortgage Banking Revenue as reported in the Company’s Consolidated Statements of Income and Comprehensive Income. The table below summarizes the notional amounts for interest rate lock commitments, best efforts forward trades and MBS forward trades pertaining to loans held for sale at December 31, 2018. Notional Interest rate lock commitments $ 49,545 Best efforts forward trades 61,865 MBS forward trades 30,000 Total derivative instruments $ 141,410 Mortgage banking derivatives, which are included in Other Assets and Other Liabilities on the Company’s Consolidated Balance Sheets, used in the ordinary course of business consist of forward sales contracts and interest rate lock commitments on residential mortgage loans. Forward sales contracts represent future commitments to deliver loans at a specified price and by a specified date and are used to manage interest rate risk on loan commitments and mortgage loans held for sale. Rate lock commitments represent commitments to fund loans at a specific rate and by a specified expiration date. These derivatives involve underlying items, such as interest rates, and are designed to mitigate risk. Notional amounts are amounts on which calculations and payments are based, but which do not represent credit exposure, as credit exposure is limited to the amounts required to be received or paid.

Loans

Loans	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Loans	(5 ) Loans The following table sets forth information concerning the loan portfolio by collateral types as of December 31, 2018 and 2017 are: December 31, 2018 December 30, 2017 Loans excluding PCI loans Real estate loans Residential $ 1,702,114 $ 1,025,303 Commercial 4,454,098 2,546,143 Land, development and construction 635,562 235,816 Total real estate 6,791,774 3,807,262 Commercial 1,183,380 693,501 Consumer and other loans 203,686 107,480 Loans before unearned fees and deferred cost 8,178,840 4,608,243 Net unearned fees and costs 2,693 820 Total loans excluding PCI loans 8,181,533 4,609,063 PCI loans (note 1) Real estate loans Residential 58,804 59,975 Commercial 87,336 92,791 Land, development and construction 7,028 6,656 Total real estate 153,168 159,422 Commercial 5,594 4,444 Consumer and other loans 209 292 Total PCI loans 158,971 164,158 Total loans 8,340,504 4,773,221 Allowance for loan losses for loans that are not PCI loans (39,579 ) (32,530 ) Allowance for loan losses for PCI loans (191 ) (295 ) Total loans, net of allowance for loan losses $ 8,300,734 $ 4,740,396 Note 1: Purchased credit-impaired (“PCI”) loans are being accounted for pursuant to ASC Topic 310-30. The following tables present the activity in the allowance for loan losses by portfolio segment for the years ended December 31, 2018, 2017 and 2016. Real Estate Loans Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses for loans that are not PCI loans: Twelve months ended December 31, 2018 Beginning of the period $ 6,003 $ 19,304 $ 1,179 $ 4,130 $ 1,914 $ 32,530 Charge-offs (516 ) (13 ) (126 ) (1,474 ) (1,706 ) (3,835 ) Recoveries 1,027 679 39 360 327 2,432 Provision for loan losses (996 ) 3,008 689 3,398 2,353 8,452 Balance at end of period $ 5,518 $ 22,978 $ 1,781 $ 6,414 $ 2,888 $ 39,579 Twelve months ended December 31, 2017 Beginning of the period $ 5,640 $ 14,713 $ 883 $ 3,785 $ 1,548 $ 26,569 Charge-offs (254 ) (74 ) — (677 ) (994 ) (1,999 ) Recoveries 950 662 596 334 217 2,759 Provision for loan losses (333 ) 4,003 (300 ) 688 1,143 5,201 Balance at end of period $ 6,003 $ 19,304 $ 1,179 $ 4,130 $ 1,914 $ 32,530 Twelve months ended December 31, 2016 Beginning of the period $ 6,015 $ 10,559 $ 936 $ 3,212 $ 1,421 $ 22,143 Charge-offs (290 ) (1,190 ) (232 ) (186 ) (849 ) (2,747 ) Recoveries 1,220 625 269 325 189 2,628 Provision for loan losses (1,305 ) 4,719 (90 ) 434 787 4,545 Balance at end of period $ 5,640 $ 14,713 $ 883 $ 3,785 $ 1,548 $ 26,569 Real Estate Loans Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses for loans that are PCI loans: Twelve months ended December 31, 2018 Beginning of the period $ — $ 59 $ 222 $ — $ 14 $ 295 Charge-offs — — — (10 ) — (10 ) Recoveries — — — 75 — 75 Provision for loan losses — (59 ) (45 ) (65 ) — (169 ) Balance at end of period $ — $ — $ 177 $ — $ 14 $ 191 Twelve months ended December 31, 2017 Beginning of the period $ 54 $ 92 $ 312 $ — $ 14 $ 472 Charge-offs — — — — — — Recoveries — 66 — — — 66 Provision for loan losses (54 ) (99 ) (90 ) — — (243 ) Balance at end of period $ — $ 59 $ 222 $ — $ 14 $ 295 Twelve months ended December 31, 2016 Beginning of the period $ — $ 103 $ 1 $ 3 $ 14 $ 121 Charge-offs — — (66 ) — — (66 ) Recoveries — — — — — — Provision for loan losses 54 (11 ) 377 (3 ) — 417 Balance at end of period $ 54 $ 92 $ 312 $ — $ 14 $ 472 The following table presents the balance in the allowance for loan losses and the recorded investment in loans by portfolio segment and based on impairment method as of December 31, 2018 and 2017. Accrued interest receivable and unearned fees/costs are not included in the recorded investment because they are not material. Real Estate Loans As of December 31, 2018 Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 331 $ 250 $ — $ 1,034 $ 1 $ 1,616 Collectively evaluated for impairment 5,187 22,728 1,781 5,380 2,887 37,963 Purchased credit-impaired — — 177 — 14 191 Total ending allowance balance $ 5,518 $ 22,978 $ 1,958 $ 6,414 $ 2,902 $ 39,770 Loans: Individually evaluated for impairment $ 6,234 $ 7,496 $ 117 $ 1,708 $ 145 $ 15,700 Collectively evaluated for impairment 1,695,880 4,446,602 635,445 1,181,672 203,541 8,163,140 Purchased credit-impaired 58,804 87,336 7,028 5,594 209 158,971 Total ending loan balances $ 1,760,918 $ 4,541,434 $ 642,590 $ 1,188,974 $ 203,895 $ 8,337,811 Real Estate Loans As of December 31, 2017 Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 586 $ — $ 4 $ 206 $ 8 $ 804 Collectively evaluated for impairment 5,417 19,304 1,175 3,924 1,906 31,726 Purchased credit-impaired — 59 222 — 14 295 Total ending allowance balance $ 6,003 $ 19,363 $ 1,401 $ 4,130 $ 1,928 $ 32,825 Loans: Individually evaluated for impairment $ 8,101 $ 8,218 $ 331 $ 3,497 $ 198 $ 20,345 Collectively evaluated for impairment 1,017,202 2,537,925 235,485 690,004 107,282 4,587,898 Purchased credit-impaired 59,975 92,791 6,656 4,444 292 164,158 Total ending loan balance $ 1,085,278 $ 2,638,934 $ 242,472 $ 697,945 $ 107,772 $ 4,772,401 The following is a summary of information regarding impaired loans at December 31, 2018 and 2017: December 31, 2018 2017 Performing TDRs (these are not included in non-performing loans ("NPLs")) $ 8,475 $ 12,081 Non-performing TDRs (these are included in NPLs) 1,002 698 Total TDRs (these are included in impaired loans) 9,477 12,779 Impaired loans that are not TDRs 6,223 7,566 Total impaired loans $ 15,700 $ 20,345 Troubled Debt Restructurings: In certain circumstances it may be beneficial to modify or restructure the terms of a loan (i.e. troubled debt restructure or “TDR”) and work with the borrower for the benefit of both parties, versus forcing the property into foreclosure and having to dispose of it in an unfavorable real estate market. When the Company modifies the terms of a loan, it usually either reduces the monthly payment and/or interest rate for generally twelve to twenty-four months. The Company has not forgiven any material principal amounts on any loan modifications to date. The Company has $9,477 of TDRs. Of this amount $8,475 are performing pursuant to their modified terms, and $1,002 are not performing and have been placed on non-accrual status and included in our non-performing loans (“NPLs”). TDRs as of December 31, 2018 and 2017 quantified by loan type classified separately as accrual (performing loans) and non-accrual (non-performing loans) are presented in the table below. As of December 31, 2018 Accruing Non-Accrual Total Real estate loans: Residential $ 5,848 $ 386 $ 6,234 Commercial 1,837 566 2,403 Land, development, construction 77 41 118 Total real estate loans 7,762 993 8,755 Commercial 577 — 577 Consumer and other 136 9 145 Total TDRs $ 8,475 $ 1,002 $ 9,477 As of December 31, 2017 Accruing Non-Accrual Total Real estate loans: Residential $ 7,737 $ 364 $ 8,101 Commercial 3,286 306 3,592 Land, development, construction 332 — 332 Total real estate loans 11,355 670 12,025 Commercial 556 — 556 Consumer and other 170 28 198 Total TDRs $ 12,081 $ 698 $ 12,779 The Company’s policy is to return non-accrual TDR loans to accrual status when all the principal and interest amounts contractually due, pursuant to its modified terms, are brought current and future payments are reasonably assured. The Company’s policy also considers the payment history of the borrower, but is not dependent upon a specific number of payments. The Company recorded a provision for loan loss expense of $77, $265 and $454 and partial charge offs of $44, $72 and $209 on TDR loans during the periods ending December 31, 2018, 2017 and 2016, respectively. Loans are modified to minimize loan losses when management believes the modification will improve the borrower’s financial condition and ability to repay the loan. The Company typically does not forgive principal. The Company generally either reduces interest rates or decreases monthly payments for a temporary period of time and those reductions of cash flows are capitalized into the loan balance. The Company may also extend maturities, convert balloon loans to longer term amortizing loans, or vice versa, or change interest rates between variable and fixed rate. Each borrower and situation is unique and management tries to accommodate the borrower and minimize the Company’s potential losses. Approximately 89% of the Company’s TDRs are current pursuant to their modified terms, and $1,002, or approximately 11% of the Company’s total TDRs are not performing pursuant to their modified terms. There does not appear to be any significant difference in success rates with one type of concession versus another. Loans modified as TDRs during the twelve month periods ending December 31, 2018, 2017 and 2016 were $1,830, $2,258 and $4,079. The Company recorded a loan loss provision of $9, $14 and $229 for loans modified during the twelve-month periods ending December 31, 2018, 2017 and 2016. The following table presents loans by class modified as TDRs for which there was a payment default within twelve months following the modification during the years ending December 31, 2018, 2017 and 2016. Period Ending Period Ending Period Ending December 31, 2018 December 31, 2017 December 31, 2016 Number Recorded Number Recorded Number Recorded of loans investment of loans investment of loans investment Residential — $ — — $ — 2 $ 167 Commercial real estate 1 433 1 177 2 936 Land, development, construction 1 49 — — — — Commercial and Industrial — — — — — — Consumer and other — — — — — — Total 2 $ 482 1 $ 177 4 $ 1,103 The Company recorded no provision for loan loss expense or partial charge offs during the year ending December 31, 2018 on TDR loans that subsequently defaulted as described above. The Company recorded $8 and $76 in provision for loan loss expense and $8 and $77 in partial charge offs during the years ending December 31, 2017 and 2016, respectively, on TDR loans that subsequently defaulted as described above. The Company has allocated $334 and $601 of specific reserves to customers whose loan terms have been modified in troubled debt restructurings as of December 31, 2018 and 2017. The Company has not committed to lend additional amounts to customers with outstanding loans that are classified as troubled debt restructurings. The following tables present loans individually evaluated for impairment by class of loans as of December 31, 2018 and 2017 excluding purchased credit-impaired loans accounted for pursuant to ASC Topic 310-30. The recorded investment is less than the unpaid principal balance primarily due to partial charge-offs. As of December 31, 2018 Unpaid principal balance Recorded investment Allowance for loan losses allocated With no related allowance recorded: Residential real estate $ 3,608 $ 3,485 $ — Commercial real estate 6,447 5,906 — Land, development, construction 144 117 — Commercial and industrial 364 353 — Consumer, other 109 108 — With an allowance recorded: Residential real estate 2,897 2,749 331 Commercial real estate 1,593 1,590 250 Land, development, construction — — — Commercial and industrial 1,378 1,355 1,034 Consumer, other 53 37 1 Total $ 16,593 $ 15,700 $ 1,616 As of December 31, 2017 Unpaid principal balance Recorded investment Allowance for loan losses allocated With no related allowance recorded: Residential real estate $ 4,945 $ 4,818 $ — Commercial real estate 8,973 8,218 — Land, development, construction 260 210 — Commercial and industrial 3,374 2,968 — Consumer, other 142 127 — With an allowance recorded: Residential real estate 3,426 3,283 586 Commercial real estate — — — Land, development, construction 140 121 4 Commercial and industrial 531 529 206 Consumer, other 78 71 8 Total $ 21,869 $ 20,345 $ 804 December 31, 2018 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 7,492 $ 308 $ — Commercial 7,876 104 — Land, development, construction 588 8 — Total real estate loans 15,956 420 — Commercial and industrial 2,081 $ 33 — Consumer and other loans 174 8 — Total $ 18,211 $ 461 $ — December 31, 2017 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 7,731 $ 267 $ — Commercial 8,956 145 — Land, development, construction 432 18 — Total real estate loans 17,119 430 — Commercial and industrial 1,968 29 — Consumer and other loans 240 10 — Total $ 19,327 $ 469 $ — December 31, 2016 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 8,384 $ 257 $ — Commercial 11,696 131 — Land, development, construction 1,503 24 — Total real estate loans 21,583 412 — Commercial and industrial 1,808 44 — Consumer and other loans 253 11 — Total $ 23,644 $ 467 $ — The following tables present the recorded investment in non-accrual loans and loans past due over 90 days still on accrual by class of loans as of December 31, 2018 and 2017 excluding purchased credit-impaired loans accounted for pursuant to ASC Topic 310-30: As of December 31, 2018 Non-accrual Loans past due over 90 days still accruing Residential real estate $ 11,488 $ — Commercial real estate 8,445 — Land, development, construction 795 — Commercial 2,274 — Consumer, other 565 — Total $ 23,567 $ — As of December 31, 2017 Non-accrual Loans past due over 90 days still accruing Residential real estate $ 7,107 $ — Commercial real estate 6,549 — Land, development, construction 138 — Commercial 3,121 — Consumer, other 373 — Total $ 17,288 $ — The following tables present the aging of the recorded investment in past due loans as of December 31, 2018 and 2017, excluding purchased credit-impaired loans accounted for pursuant to ASC Topic 310-30: Accruing Loans Total 30 - 59 days past due 60 - 89 days past due Greater than 90 days past due Total Past Due Loans Not Past Due Non-accrual Loans As of December 31, 2018 Residential real estate $ 1,702,114 $ 5,730 $ 5,631 $ — $ 11,360 $ 1,679,266 $ 11,488 Commercial real estate 4,454,098 10,840 4,607 — 15,446 4,430,207 8,445 Land/dev/construction 635,562 661 4,022 — 4,683 630,084 795 Commercial 1,183,380 2,803 878 — 3,681 1,177,425 2,274 Consumer 203,686 1,061 271 — 1,332 201,789 565 $ 8,178,840 $ 21,094 $ 15,408 $ — $ 36,502 $ 8,118,771 $ 23,567 Accruing Loans Total 30 - 59 days past due 60 - 89 days past due Greater than 90 days past due Total Past Due Loans Not Past Due Non-accrual Loans As of December 31, 2017 Residential real estate $ 1,025,303 $ 3,568 $ 1,821 $ — $ 5,389 $ 1,012,807 $ 7,107 Commercial real estate 2,546,143 1,158 2,272 — 3,430 2,536,164 6,549 Land/dev/construction 235,816 2,807 189 — 2,996 232,682 138 Commercial 693,501 568 763 — 1,331 689,049 3,121 Consumer 107,480 471 48 — 519 106,588 373 $ 4,608,243 $ 8,572 $ 5,093 $ — $ 13,665 $ 4,577,290 $ 17,288 Credit Quality Indicators: The Company categorizes loans into risk categories based on relevant information about the ability of borrowers to service their debt such as: current financial information, historical payment experience, credit documentation, public information, and current economic trends, among other factors. The Company analyzes loans individually by classifying the loans as to credit risk. This analysis is performed on at least an annual basis. The Company uses the following definitions for risk ratings: Special Mention: Loans classified as special mention have a potential weakness that deserves management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the loan or of the institution’s credit position at some future date. Substandard: Loans classified as substandard are inadequately protected by the current net worth and paying capacity of the obligor or of the collateral pledged, if any. Loans so classified have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that the institution will sustain some loss if the deficiencies are not corrected. Doubtful: Loans classified as doubtful have all the weaknesses inherent in those classified as substandard, with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, conditions, and values, highly questionable and improbable. Loans not meeting the criteria above that are analyzed individually as part of the above described process are considered to be pass rated loans. As of December 31, 201 8 and 2017 , and based on the most recent analysis performed, the risk category of loans by class of loans, excluding purchased credit - impaired loans accounted for pursuant to ASC Topic 310-30, is presented below. The increase in loans categorized as special mention between the periods presented is due to the acquisitions of Sunshine and Harbor on January 1, 2018 and Charter on September 1 , 201 8 , respectively. As of December 31, 2018 Loan Category Pass Special Mention Substandard Doubtful Residential real estate $ 1,633,810 $ 41,522 $ 26,782 $ — Commercial real estate 4,246,687 160,981 46,430 — Land/dev/construction 610,631 20,586 4,345 — Commercial 1,137,272 40,836 5,272 — Consumer 202,701 247 738 — Total $ 7,831,100 $ 264,172 $ 83,568 $ — As of December 31, 2017 Loan Category Pass Special Mention Substandard Doubtful Residential real estate $ 987,472 $ 20,435 $ 17,396 $ — Commercial real estate 2,411,085 115,942 19,116 — Land/dev/construction 217,555 17,699 562 — Commercial 674,764 14,186 4,551 — Consumer 106,735 139 606 — Total $ 4,397,611 $ 168,401 $ 42,231 $ — The Company considers the performance of the loan portfolio and its impact on the allowance for loan losses. For residential and consumer loan classes, the Company also evaluates credit quality based on the aging status of the loan, which was previously presented, and by payment activity. The following table presents the recorded investment in residential and consumer loans, excluding purchased credit-impaired loans accounted for pursuant to ASC Topic 310-30, based on payment activity as of December 31, 2018 and 2017: As of December 31, 2018 Residential Consumer Performing 1,690,626 203,121 Non-performing 11,488 565 Total 1,702,114 203,686 As of December 31, 2017 Residential Consumer Performing $ 1,018,196 $ 107,107 Non-performing 7,107 373 Total $ 1,025,303 $ 107,480 Purchased Credit - Impaired (“PCI”) Loans: Income is recognized on PCI loans pursuant to ASC Topic 310-30. A portion of the fair value discount has been ascribed as an accretable yield that is accreted into interest income over the estimated remaining life of the loans. The remaining non-accretable difference represents cash flows not expected to be collected. The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and carrying value of the loans as of December 31, 2018, 2017 and 2016. Contractually required principal and interest payments have been adjusted for estimated prepayments. December 31, 2018 2017 2016 Contractually required principal and interest $ 267,815 $ 248,283 $ 297,821 Non-accretable difference (38,602 ) (13,183 ) (18,372 ) Cash flows expected to be collected 229,213 235,100 279,449 Accretable yield (70,242 ) (70,942 ) (93,525 ) Carrying value of acquired loans 158,971 164,158 185,924 Allowance for loan losses (191 ) (295 ) (472 ) Carrying value less allowance for loan losses $ 158,780 $ 163,863 $ 185,452 The Company recorded $(169), $(243) and $417 in loan loss provision (recovery) expense on PCI loans during the years ending December 31, 2018, 2017 and 2016, respectively. The Company adjusted its estimates of future expected losses, cash flows and renewal assumptions during the current year. These adjustments resulted in an increase in expected cash flows and accretable yield, and a decrease in the non-accretable difference. The Company reclassified approximately $22,469, $4,707 and $6,220 from non-accretable difference to accretable yield during the twelve-month periods ending December 31, 2018, 2017 and 2016, respectively, to reflect the adjusted estimates of future expected cash flows. The Company recognized approximately $35,944 of accretion income during the twelve-month period ending December 31, 2018. The table below summarizes the changes in total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and carrying value of the loans during the periods ending December 31, 2018, 2017 and 2016. Effect of income all other December 31, 2017 acquisitions accretion adjustments December 31, 2018 Contractually required principal and interest $ 248,283 $ 122,392 $ — $ (102,860 ) $ 267,815 Non-accretable difference (13,183 ) (58,927 ) — 33,508 (38,602 ) Cash flows expected to be collected 235,100 63,465 — (69,352 ) 229,213 Accretable yield (70,942 ) (7,770 ) 35,944 (27,474 ) (70,242 ) Carry value of acquired loans $ 164,158 $ 55,695 $ 35,944 $ (96,826 ) $ 158,971 Effect of income all other December 31, 2016 acquisitions accretion adjustments December 31, 2017 Contractually required principal and interest $ 297,821 $ 31,334 $ — $ (80,872 ) $ 248,283 Non-accretable difference (18,372 ) (7,104 ) — 12,293 (13,183 ) Cash flows expected to be collected 279,449 24,230 — (68,579 ) 235,100 Accretable yield (93,525 ) (4,185 ) 32,388 (5,620 ) (70,942 ) Carry value of acquired loans $ 185,924 $ 20,045 $ 32,388 $ (74,199 ) $ 164,158 Effect of income all other December 31, 2015 acquisitions accretion adjustments December 31, 2016 Contractually required principal and interest $ 332,570 $ 73,005 $ — $ (107,754 ) $ 297,821 Non-accretable difference (19,452 ) (9,295 ) — 10,375 (18,372 ) Cash flows expected to be collected 313,118 63,710 — (97,379 ) 279,449 Accretable yield (102,590 ) (18,585 ) 34,006 (6,356 ) (93,525 ) Carry value of acquired loans $ 210,528 $ 45,125 $ 34,006 $ (103,735 ) $ 185,924

Other Real Estate Owned

Other Real Estate Owned	12 Months Ended
	Dec. 31, 2018
Real Estate [Abstract]
Other Real Estate Owned	(6 ) Other real estate owned Other real estate owned means real estate acquired through or instead of loan foreclosure. Activity in the valuation allowance was as follows: 2018 2017 2016 Beginning of year $ 861 $ 869 $ 1,297 Valuation write down of repossessed real estate 482 682 871 Sales and/or dispositions (939 ) (690 ) (1,299 ) End of year $ 404 $ 861 $ 869 Expenses related to foreclosed real estate include: 2018 2017 2016 Gain on sale of repossessed real estate $ (1,933 ) (876 ) (1,528 ) Valuation write down of repossessed real estate 482 682 871 Operating expenses, net of rental income 2,815 2,252 2,392 Total $ 1,364 $ 2,058 $ 1,735

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value	(7 ) Fair value Generally accepted accounting principles establish a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard describes three levels of inputs that may be used to measure fair value: Level 1: Quoted prices (unadjusted) for identical assets or liabilities in active markets that the entity has the ability to access as of the measurement date. Level 2: Significant other observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. Level 3: Significant unobservable inputs that reflect a reporting entity’s own assumptions about the assumptions that market participants would use in pricing an asset or liability. The fair values of available for sale debt securities are determined by obtaining quoted prices on nationally recognized securities exchanges (Level 1 inputs) or matrix pricing, which is a mathematical technique widely used in the industry to value debt securities without relying exclusively on quoted prices for the specific securities but rather by relying on the securities’ relationship to other benchmark quoted securities (Level 2 inputs). The fair values of corporate debt securities are calculated using market indicators such as broker quotes (Level 2). The fair values of trading securities are determined as follows: (1) for those securities that have traded prior to the date of the consolidated balance sheet but have not settled (date of sale) until after such date, the sales price is used as the fair value; and, (2) for those securities which have not traded as of the date of the consolidated balance sheet, the fair value was determined by broker price indications of similar or same securities. The Company has the rights to service a portfolio of Fannie Mae ("FNMA") and other loans sold on a servicing retained basis. The fair value of mortgage servicing assets are measured when the loan is sold and subsequently measured at fair value on a recurring basis. Management uses a model operated and maintained by a third party to calculate the present value of future cash flows using the third party's market-based assumptions. The future cash flows for each asset are based on the asset's unique characteristics and the third party's market-based assumptions for prepayment speeds, default and voluntary prepayments (Level 2). Adjustments to fair value are recorded as a component of Mortgage Banking Revenue in the Consolidated Statements of Income and Comprehensive Income. Effective January 1, 2018, the Company elected to account for mortgage loans held for sale under the fair value option with changes in fair value recognized in current period earnings. For periods prior to December 31, 2017, these loans were valued at the lower of cost or fair value. These loans are intended for sale and the Company believes that the fair value is the best indicator of the resolution of these loans (Level 2). In conjunction with the fair value election on loans held for sale, Mortgage banking uses derivative forward sales contracts and interest rate lock commitments on residential mortgage loans. Fair values of these mortgage derivatives are estimated based on changes in market prices for mortgage forward trades and mortgage interest rates (Level 2) and estimated pull through percentages from the date the interest on the loan is locked (Level 3). The Company has the rights to service a portfolio of Fannie Mae ("FNMA") and other government guaranteed loans sold on a servicing retained basis. Mortgage servicing assets are measured at fair value when the loan is sold and subsequently measured at fair value on a recurring basis utilizing Level 2 inputs. Management uses a model operated and maintained by a third party to calculate the present value of future cash flows using the third party's market-based assumptions. The future cash flows for each asset are based on the asset's unique characteristics and the third party's market-based assumptions for prepayment speeds, default and voluntary prepayments. Adjustments to fair value are recorded as a component of Mortgage Banking Revenue in the Consolidated Statements of Income and Comprehensive Income. The fair value of interest rate swap derivatives is based on valuation models using observable market data as of the measurement date (Level 2). The derivatives are traded in an over-the-counter market where quoted market prices are not always available. Therefore, fair values of derivatives are determined using quantitative models that utilize multiple market inputs. The inputs will vary based on the type of derivative, but could include interest rates, prices and indices to generate continuous yield or pricing curves, prepayment rates, and volatility factors to value the position. The majority of market inputs are actively quoted and can be validated through external sources, including brokers, market transactions and third-party pricing services. The fair value of impaired loans with specific valuation allowance for loan losses and other real estate owned is based on recent real estate appraisals. For residential real estate impaired loans and other real estate owned, appraised values are based on the comparative sales approach. For commercial and commercial real estate impaired loans and other real estate owned, appraisers may use either a single valuation approach or a combination of approaches such as comparative sales, cost or the income approach. A significant unobservable input in the income approach is the estimated income capitalization rate for a given piece of collateral. At December 31, 2018, the range of capitalization rates utilized to determine the fair value of the underlying collateral ranged from 7% to 10%. Adjustments to comparable sales may be made by the appraiser to reflect local market conditions or other economic factors and may result in changes in the fair value of a given asset over time. As such, the fair value of impaired loans and other real estate owned are considered a Level 3 in the fair value hierarchy. Assets and liabilities measured at fair value on a recurring basis are summarized below. Fair value measurements using Significant Quoted prices in other Significant active markets for observable unobservable Carrying identical assets inputs inputs value (Level 1) (Level 2) (Level 3) at December 31, 2018 Assets: Trading securities $ 1,737 — $ 1,737 — Available for sale debt securities Corporate debt securities 6,427 — 6,427 — Obligations of U.S. government sponsored entities and agencies 37,868 — 37,868 — Mortgage backed securities 1,594,275 — 1,594,275 — Municipal securities 88,778 — 88,778 — Loans held for sale, at fair value 40,399 — 40,399 — Mortgage servicing assets 1,565 — 1,565 — Mortgage banking derivatives 783 — — 783 Interest rate swap derivatives 92,475 — 92,475 — Liabilities: Mortgage banking derivatives 169 — 164 5 Interest rate swap derivatives 92,892 — 92,892 — at December 31, 2017 Assets: Trading securities $ 6,777 — $ 6,777 — Available for sale debt securities U.S. Treasury securities 5,200 — 5,200 — Obligations of U.S. government sponsored entities and agencies 9,574 — 9,574 — Mortgage backed securities 972,611 — 972,611 — Municipal securities 72,758 — 72,758 — Interest rate swap derivatives 42,480 — 42,480 — Liabilities: Interest rate swap derivatives 43,259 — 43,259 — Assets and liabilities measured at fair value on a non-recurring basis are summarized below. Fair value measurements using Significant Quoted prices in other Significant active markets for observable unobservable Carrying identical assets inputs inputs value (Level 1) (Level 2) (Level 3) at December 31, 2018 Assets: Impaired loans Residential real estate $ 1,811 — — $ 1,811 Commercial real estate 5,614 — — 5,614 Land, land development and construction 90 — — 90 Commercial 1,274 — — 1,274 Consumer 40 — — 40 Other real estate owned Land, land development and construction 867 — — 867 Bank property held for sale 5,805 — — 5,805 at December 31, 2017 Assets: Impaired loans Residential real estate $ 2,423 — — $ 2,423 Commercial real estate 6,293 — — 6,293 Land, land development and construction 292 — — 292 Commercial 2,131 — — 2,131 Consumer 57 — — 57 Other real estate owned Residential real estate 635 — — 635 Commercial real estate 261 — — 261 Land, land development and construction 1,481 — — 1,481 Bank property held for sale 1,516 — — 1,516 Impaired loans measured at fair value had a recorded investment of $8,829 with a valuation allowance of $1,463 at December 31, 2018, and a recorded investment of $11,673, with a valuation allowance of $477, at December 31, 2017. The Company recorded a provision for loan loss expense of $1,363 and $842 on these loans during the years ending 2018 and 2017, respectively. Other real estate owned had a decline in fair value of $482 and $682 during the twelve-month periods ending December 31, 2018 and 2017, respectively. Changes in fair value were recorded directly as an adjustment to current earnings through non-interest expense. Bank property held for sale represents certain branch office buildings which the Company has closed and consolidated with other existing branches or acquired through various acquisitions. The real estate was transferred out of the Bank Premises and Equipment category into Bank Property Held For Sale at the lower of amortized cost or fair value less estimated costs to sell. The fair values were based upon appraisals. The Company recorded an impairment charge, of $2,667 and $519 during the twelve month periods ending December 31, 2018 and 2017 related to bank properties held for sale. Fair Value of Financial Instruments : The methods and assumptions, not previously presented, used to estimate fair value are described as follows: Cash and Cash Equivalents: FHLB, FRB and other stock Investment securities held to maturity : The fair values of securities held to maturity are determined by obtaining quoted prices on nationally recognized securities exchanges (Level 1 inputs) or matrix pricing, which is a mathematical technique widely used in the industry to value debt securities without relying exclusively on quoted prices for the specific securities but rather by relying on the securities’ relationship to other benchmark quoted securities (Level 2 inputs). Loans, net Accrued Interest Receivable Deposits Other Borrowings Corporate Debentures Accrued Interest Payable Off-balance Sheet Instruments The following table presents the carry amounts and estimated fair values of the Company’s financial instruments: Fair value measurements at December 31, 2018 Carrying amount Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents $ 367,333 $ 367,333 $ — $ — $ 367,333 Trading securities 1,737 — 1,737 — 1,737 Available for sale debt securities 1,727,348 — 1,727,348 — 1,727,348 Held to maturity debt securities 216,833 — 212,179 — 212,179 FHLB, FRB and other stock 79,584 — — — n/a Loans held for sale, at fair value 40,399 — 40,399 — 40,399 Loans, net 8,300,734 — — 8,342,220 8,342,220 Mortgage servicing assets 1,565 — 1,565 — 1,565 Mortgage banking derivatives 783 — — 783 783 Interest rate swap derivatives 92,475 — 92,475 — 92,475 Accrued interest receivable 33,143 — 8,355 24,788 33,143 Financial liabilities: Deposits- without stated maturities $ 7,655,376 $ 7,655,376 $ — $ — $ 7,655,376 Deposits- with stated maturities 1,821,960 — 1,827,299 — 1,827,299 Securities sold under agreement to repurchase 57,772 — 57,772 — 57,772 Federal funds purchased and other borrowings 655,360 — 655,360 — 655,360 Corporate debentures 32,415 — — 28,621 28,621 Mortgage banking derivatives 169 — 164 5 169 Interest rate swap derivatives 92,892 — 92,892 — 92,892 Accrued interest payable 2,627 — 2,627 — 2,627 Fair value measurements at December 31, 2017 Carrying amount Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents $ 280,619 $ 280,619 $ — $ — $ 280,619 Trading securities 6,777 — 6,777 — 6,777 Available for sale debt securities 1,060,143 — 1,060,143 — 1,060,143 Held to maturity debt securities 232,399 — 231,615 — 231,615 FHLB, FRB and other stock 34,876 — — — n/a Loans held for sale 19,647 — 19,647 — 19,647 Loans, net 4,740,396 — — 4,731,514 4,731,514 Interest rate swap derivatives 42,480 — 42,480 — 42,480 Accrued interest receivable 18,628 — 5,370 13,258 18,628 Financial liabilities: Deposits- without stated maturities $ 4,727,840 $ 4,727,840 $ — $ — $ 4,727,840 Deposits- with stated maturities 832,683 — 845,039 — 845,039 Securities sold under agreement to repurchase 52,080 — 52,080 — 52,080 Federal funds purchased and other borrowings 331,490 — 331,490 — 331,490 Corporate debentures 26,192 — — 22,363 22,363 Interest rate swap derivatives 43,259 — 43,259 — 43,259 Accrued interest payable 1,169 — 1,169 — 1,169

Bank Premises and Equipment

Bank Premises and Equipment	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Bank Premises and Equipment	(8 ) Bank Premises and Equipment A summary of bank premises and equipment as of December 31, 2018 and 2017 is as follows: December 31, 2018 2017 Land $ 72,487 $ 51,724 Land improvements 1,381 1,251 Buildings 130,424 85,625 Leasehold improvements 13,655 6,575 Furniture, fixtures and equipment 45,056 38,662 Construction in progress 15,491 4,783 278,494 188,620 Less: Accumulated depreciation 51,040 46,734 $ 227,454 $ 141,886 The Company leases land and certain facilities under noncancellable operating leases. The following is a schedule of future minimum annual rentals under the noncancellable operating leases: Year ending December 31, 2018 7,113 2019 5,687 2020 5,004 2021 4,274 2022 3,163 Thereafter 15,047 $ 40,288 Rent expense, net of rental income, for the years ended December 31, 2018, 2017 and 2016, was $5,642, $2,996 and $1,955, respectively, and is included in Occupancy Expense in the accompanying Consolidated Statements of Income and Comprehensive Income. Rental income for the years ended December 31, 2018, 2017 and 2016, was $1,183, $930, and $892, respectively, and is included in occupancy expense.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	(9 ) Goodwill and Intangible Assets Goodwill Goodwill was a result of whole bank acquisitions, all within the Company’s commercial and retail banking segment. The change in balance for goodwill during the years 2018, 2017 and 2016 is as follows: 2018 2017 2016 Beginning of year $ 257,683 $ 106,028 $ 76,739 Acquired goodwill 545,197 151,655 29,289 Impairment — — — End of year $ 802,880 $ 257,683 $ 106,028 The Company performed a step 1 annual impairment analysis of the goodwill recorded at the commercial and retail banking (“Bank”) reporting unit as of November 30, 2018. Step 1 includes the determination of the carrying value of the reporting unit, including the existing goodwill and intangible assets, and estimating the fair value of the reporting unit. The carrying amount of the reporting unit did not exceed its fair value resulting in no impairment. Core Deposit and Trust Intangible Assets Intangible assets consists of core deposit intangibles (“CDI”) and Trust intangible (“Trust”) which are from either whole bank or branch acquisitions. Acquired CDI and Trust are initially measured at fair value and then amortized over a ten-year period on an accelerated basis using the projected decay rates of the underlying core deposits in the case of CDI , an accelerated method in the case of the Trust intangible . In December 201 7 , the Company sold its trust department resulting in the disposal of its related trust intangible asset. The change in balance for the CDI and Trust intangible assets during the years 2018, 2017 and 2016 is as follows: 2018 2017 2016 Beginning of year $ 24,063 $ 16,209 $ 13,001 Acquired CDI 51,945 12,424 6,282 Amortization expense on CDI and Trust (9,783 ) (3,997 ) (3,074 ) Disposal of Trust intangible asset — (573 ) — End of year $ 66,225 $ 24,063 $ 16,209 CDI and Trust intangible assets for years ended December 31, 2018 and 2017 were as follows: December 31, 2018 December 31, 2017 Gross Gross Carrying Accumulated Carrying Accumulated Amount Amortization Amount Amortization Amortized intangible assets: Core deposit intangibles $ 93,964 $ 27,739 $ 42,019 $ 17,956 Total acquired intangibles $ 93,964 $ 27,739 $ 42,019 $ 17,956 Estimated amortization expense for each of the next five years: CDI 2019 $ 10,479 2020 9,111 2021 7,923 2022 7,245 2023 7,165 Mortgage and Small Business Administration Servicing Assets Mortgage servicing assets (“MSA”) and small business administration (“SBA”) servicing assets are either originated by the Company’s commercial and retail banking business or obtained from whole bank acquisitions. The Company acquired a total of $1,828 MSA and SBA servicing assets through its acquisition of Charter on September 1, 2018. As these servicing rights were acquired at fair value as of acquisition date, no impairment charge has currently been assessed on these assets. Mortgage Servicing Assets Activity for MSA and the related valuation allowance follows: 2018 Beginning of year $ — Effect from acquisitions 1,602 Changes in fair value (37 ) End of year $ 1,565 Fair value at year end 2018 was determined using discount rates ranging from 0.4% to 1.1%, prepayment speeds ranging from 6.6% to 15.5%, depending on the stratification of the specific right, and a weighted average default rate of 0.5%. S mall B usiness A dministration Servicing Asset s During the year ended December 31, 2018, the Company acquired $226 of SBA loans serviced for others in the acquisition of Charter (see Note 26 “Business Combinations”, for further information). The Company had a total of $35,779, The Company recorded $235 and $69 of amortization on the SBA servicing assets during the years ended December 31, 2018 and 2017, respectively. As the SBA servicing assets from the Charter acquisition was assumed at fair value on September 1, 2018, no impairment charge has currently been assessed on these assets. SBA servicing assets totaled $1,388 and $551 at December 31, 2018 and 2017, respectively. The risk inherent in SBA servicing assets includes prepayments at different rates than anticipated or resolution of loans at dates not consistent with the estimated expected lives. These events would cause the value of the SBA servicing assets to decline at a faster or slower rate than originally anticipated. Activity for SBA servicing assets is as follows: 2018 2017 Beginning of year $ 551 $ 85 Additions 846 535 Effect from acquisitions 226 — Amortized to expense (235 ) (69 ) End of year $ 1,388 $ 551

Deposits

Deposits	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Deposits	(10 ) Deposits A detail of deposits at December 31, 2018 and 2017 is as follows: December 31, Weighted Weighted Average Average Interest Interest 2018 Rate 2017 Rate Non-interest bearing deposits $ 2,923,640 — % $ 1,999,901 — % Interest bearing deposits: Interest bearing demand deposits 1,811,006 0.3 % 1,058,985 0.1 % Savings deposits 704,159 0.1 % 501,014 0.1 % Money market accounts 2,216,571 0.9 % 1,167,940 0.4 % Time deposits less than $100,000 871,043 1.6 % 384,347 1.0 % Time deposits of $100,000 or greater 950,917 1.6 % 448,336 1.2 % $ 9,477,336 0.6 % $ 5,560,523 0.3 % The following table presents the amount of certificate accounts at December 31, 2018, maturing during the periods reflected below: Year Amount 2019 $ 1,337,688 2020 320,487 2021 89,880 2022 39,552 2023 33,965 Thereafter 388 Total $ 1,821,960 Time deposits that meet or exceed the FDIC insurance limit of $250 at year end 2018 and 2017 were $397,369 and $197,247. Total brokered deposits were $328,718 and $222,368 at year end 2018 and 2017, respectively.

Securities Sold Under Agreement

Securities Sold Under Agreements to Repurchase	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Securities Sold Under Agreements to Repurchase	(11 ) Securities Sold Under Agreements to Repurchase The Company’s subsidiary bank enters into borrowing arrangements with its retail business customers by agreements to repurchase (“repurchase agreements”) under which the bank pledges investment securities owned and under its control as collateral against the one-day borrowing arrangement. At December 31, 2018 and 2017, the Company had $57,772 and $52,080 in repurchase agreements. Repurchase agreements are secured by obligations of U.S. government agencies and municipal securities with fair values of $64,706 and $59,682 at December 31, 2018 and 2017, respectively. Any risk related to these arrangements, primarily market value changes, is minimized due to the overnight (one-day) maturity and the additional collateral pledged over the borrowed amounts. The following tables provide additional details as of December 31, 2018 and 2017. MBS Municipal As of December 31, 2018 Securities Securities Total Market value of securities pledged $ 64,269 $ 437 $ 64,706 Borrowings related to pledged amounts 57,594 178 57,772 Market value pledged as a % of borrowings 112 % 246 % 112 % MBS Municipal As of December 31, 2017 Securities Securities Total Market value of securities pledged $ 59,239 $ 443 $ 59,682 Borrowings related to pledged amounts 52,030 50 52,080 Market value pledged as a % of borrowings 114 % 886 % 115 % Information concerning repurchase agreements is summarized as follows: 2018 2017 2016 Average daily balance during the year $ 54,344 $ 43,850 $ 29,435 Average interest rate during the year 1.16 % 0.56 % 0.35 % Maximum month-end balance during the year $ 59,751 $ 52,080 $ 35,500 Weighted average interest rate at year end 1.66 % 0.88 % 0.33 %

Federal Funds Purchased

Federal Funds Purchased	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Federal Funds Purchased	(1 2 ) Federal Funds Purchased Federal funds purchased, as listed below, are overnight deposits including deposits from correspondent banks. At December 31, 2017, the Company also had $70,000 in overnight borrowings, with a weighted average interest rate of 1.63%, with the Federal Reserve Bank and financial institutions. These borrowings are included in Federal Funds Purchased on the Company’s Consolidated Balance Sheets. Information concerning these deposits is summarized as follows: 2018 2017 2016 Average daily balance during the year $ 250,499 $ 263,669 $ 210,276 Average interest rate during the period 2.02 % 1.13 % 0.55 % Maximum month-end balance during the year $ 294,360 $ 335,531 $ 288,582 Weighted average interest rate at year end 2.07 % 1.39 % 0.72 %

Other Borrowed Funds

Other Borrowed Funds	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Other Borrowed Funds	(1 3 ) Other Borrowed Funds From time to time, the Company borrows either through Federal Home Loan Bank advances or one-day borrowings, other than correspondent bank deposits listed in Note 12 above. At year end, advances from the Federal Home Loan Bank were as follows: 2018 2017 Fixed rate advances, maturity through 01/28/2019, rates from 2.45% and 2.54%, averaging 2.50% $ 200,000 $ — Floating rate advances, rates of 2.65% and 1.59%, as of December 31, 2018 and 2017, respectively 150,000 155,000 Total $ 350,000 $ 155,000 Federal Home Loan Bank advances are collateralized by residential and commercial loans under a blanket lien arrangement and investment securities. Based on this collateral, and the Company’s holdings of FHLB stock, the Company is eligible to borrow up to $871,067 at year end 2018. The Company has $50,000 available in a revolving line of credit, with an interest rate of LIBOR plus 350 basis points (“bps”) and scheduled to mature on April 1, 2021. No revolving line of credit balance was outstanding as of December 31, 2018. For year ended December 31, 2017, the Company had $20,000 outstanding in this revolving line of credit with an interest rate of 4.84%. On January 1, 2018, the Company acquired all the assets and assumed all the liabilities of Sunshine pursuant to the merger agreement, including Sunshine’s debt obligations. In March 2016, Sunshine accepted subscriptions for and sold, at 100% of their principal amount, an aggregate of $11,000 of subordinated notes (the “Notes”), on a private placement basis, to two accredited investors. The Notes bear interest at a fixed interest rate of 5.0% per year. The Notes have a term of five years, and have a maturity date of April 1, 2021. The Notes are redeemable at the option of the Company, in whole or in part, at any time, without penalty or premium, subject to any required regulatory approvals. The Federal Home Loan Bank Advances, revolving line of credit and Notes are included in Other Borrowed Funds on the Company’s Consolidated Balance Sheets.

Corporate Debentures

Corporate Debentures	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Corporate Debentures	(1 4 ) Corporate Debentures In September 2003, the Company formed CenterState Banks of Florida Statutory Trust I (the “Trust”) for the purpose of issuing trust preferred securities. On September 22, 2003, the Company issued a floating rate corporate debenture in the amount of $10,000. The Trust used the proceeds from the issuance of a trust preferred security to acquire the corporate debenture. The trust preferred security essentially mirrors the corporate debenture, carrying a cumulative preferred dividend at a variable rate equal to the interest rate on the corporate debenture (three month LIBOR plus 305 basis points (“bps”)). The corporate debenture and the trust preferred security each have 30-year In September 2004, Valrico Bancorp Inc. (“VBI”) formed Valrico Capital Statutory Trust (“Valrico Trust”) for the purpose of issuing trust preferred securities. On September 9, 2004, VBI issued a floating rate corporate debenture in the amount of $2,500. The Trust used the proceeds from the issuance of a trust preferred security to acquire the corporate debenture. On April 2, 2007, the Company acquired all the assets and assumed all the liabilities of VBI pursuant to the merger agreement, including VBI’s corporate debenture and related trust preferred security discussed above. The trust preferred security essentially mirrors the corporate debenture, carrying a cumulative preferred dividend at a variable rate equal to the interest rate on the corporate debenture (three month LIBOR plus 270 bps). The corporate debenture and the trust preferred security each have 30-year In September 2003, Federal Trust Corporation (“FTC”) formed Federal Trust Statutory I (“FTC Trust”) for the purpose of issuing trust preferred securities. On September 17, 2003, FTC issued a floating rate corporate debenture in the amount of $5,000. The Trust used the proceeds from the issuance of a trust preferred security to acquire the corporate debenture. In November 2011, the Company acquired certain assets and assumed certain liabilities of FTC from The Hartford Financial Services Group, Inc. (“Hartford”) pursuant to an acquisition agreement, including FTC’s corporate debenture and related trust preferred security issued through FTC’s finance subsidiary FTC Trust. The trust preferred security essentially mirrors the corporate debenture, carrying a cumulative preferred dividend at a variable rate equal to the interest rate on the corporate debenture ( three month LIBOR plus 295 b p s ). The corporate debenture and the trust preferred security each have 30-year lives maturing in 2033 . The trust preferred security and the corporate debenture are callable by the Company or the FTC Trust, at their respective option after five years , and sooner in specific events, subject to prior approval by the Federal Reserve, if then required. The Company has treated the corporate debenture as Tier 1 capital up to the maximum amount allowed under the Federal Reserve guidelines for federal regulatory purposes. The Company is not considered the primary beneficiary of this Trust (variable interest entity), therefore the trust is not consolidated in the Company’s financial statements, but rather the subordinated debentures are shown as a liability. The Company’s investment in the common stock of the trust was $ 155 and is included in other assets. In December 2004, Gulfstream Bancshares, Inc. (“GBI”) formed Gulfstream Bancshares Capital Trust I (“GBI Trust I”) for the purpose of issuing trust preferred securities. On December 1, 2004, GBI issued a floating rate corporate debenture in the amount of $7,000. The Trust used the proceeds from the issuance of a trust preferred security to acquire the corporate debenture. The trust preferred security essentially mirrors the corporate debenture, carrying a cumulative preferred dividend at a variable rate equal to the interest rate on the corporate debenture (three month LIBOR plus 190 bps). The rate is subject to change quarterly. The corporate debenture and the trust preferred security each have 30-year In December 2006, GBI formed Gulfstream Bancshares Capital Trust II (“GBI Trust II”) for the purpose of issuing trust preferred securities. On December 28, 2006, GBI issued a floating rate corporate debenture in the amount of $3,000. The Trust used the proceeds from the issuance of a trust preferred security to acquire the corporate debenture. The trust preferred security essentially mirrors the corporate debenture, carrying a cumulative preferred dividend at a variable rate equal to the interest rate on the corporate debenture (three month LIBOR plus 170 bps). The rate is subject to change quarterly. The corporate debenture and the trust preferred security each have 30-year In July 2006, Hometown formed Homestead Statutory Trust I (“Homestead Trust I”) for the purpose of issuing trust preferred securities. On July 17, 2006, Hometown issued a floating rate corporate debenture in the amount of $16,000. The Trust used the proceeds from the issuance of a trust preferred security to acquire the corporate debenture. The trust preferred security essentially mirrors the corporate debenture, carrying a cumulative preferred dividend at a variable rate equal to the interest rate on the corporate debenture (three month LIBOR plus 165 bps). The rate is subject to change quarterly. The corporate debenture and the trust preferred security each have 30-year In January 2018, the Company assumed BSA Financial Statutory Trust I (“BSA”) and MRCB Statutory Trust II (“MRCB”) from its acquisition of HCBF. These Trusts were acquired by HCBF in prior acquisitions completed by HCBF. The issued floating rate corporate debentures related to BSA and MRCB were in the amounts of $5,000 and $3,000, respectively. The trust preferred security essentially mirror the corporate debentures, carrying a cumulative preferred dividend at a variable rate equal to the interest rate on the corporate debentures (three month LIBOR plus 155 bps and LIBOR plus 160 bps, respectively). The rates are subject to change quarterly. The corporate debentures and the trust preferred securities each have 30-year Tier 1 capital up to the maximum amount allowed under the Federal Reserve guidelines for federal regulatory purposes. The Company is not considered the primary beneficiary of these trusts (variable interest entities), therefore the trusts are not consolidated in the Company’s financial statements, but rather the subordinated debentures are shown as a liability. The Company’s investments in the common stock of the trusts were $ 155 and $ 93 , respectively, and are included in Other Assets. In September 2018, the Company assumed CBS Financial Capital Trust I (“CBS Trust I”) and CBS Financial Capital Trust II (“CBS Trust II”) pursuant to its acquisition of Charter, in the amounts of $4,000 and $5,000, respectively. CBS Trust I and CBS Trust II were subsequently redeemed in December 2018, at par with no gains or losses realized on the termination of debt, with prior approval by the Federal Reserve.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	(15) Income Taxes Allocation of federal and state income tax expense between current and deferred portions for the years ended December 31, 2018, 2017 and 2016, is as follows: Current Deferred Total December 31, 2018: Federal $ 14,273 $ 16,843 $ 31,116 State 5,240 4,668 9,908 $ 19,513 $ 21,511 $ 41,024 December 31, 2017: Federal $ 18,243 $ 29,393 $ 47,636 State 4,045 1,799 5,844 $ 22,288 $ 31,192 $ 53,480 December 31, 2016: Federal $ 15,172 $ 3,127 $ 18,299 State 3,091 520 3,611 $ 18,263 $ 3,647 $ 21,910 The tax effect of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2018 and 2017, are presented below: December 31, 2018 2017 Deferred tax assets: Allowance for loan losses $ 10,079 $ 8,320 Stock based compensation 1,701 1,609 Deferred compensation 2,235 1,488 Impairment expenses 1,334 572 Net operating loss carryforward 18,313 13,278 Other real estate owned expenses 177 557 Fair value adjustments 17,929 13,414 Non-accrual interest 2,890 1,385 Unrealized loss on available for sale debt securities 7,611 2,378 Other — 2,339 Total deferred tax assets 62,269 45,340 Deferred tax liabilities: Premises and equipment, due to differences in depreciation methods and useful lives (8,145 ) (5,441 ) Deferred loan costs, net (683 ) (208 ) Prepaid expenses (1,608 ) (1,752 ) Like kind exchange (197 ) (197 ) Accretion of discounts on investments (67 ) (17 ) Other (107 ) — Total deferred tax liabilities (10,807 ) (7,615 ) Net deferred tax asset $ 51,462 $ 37,725 As a result of the acquisition of First Southern on June 1, 2014, the Company obtained net operating loss carryforwards of approximately $57,375 which are subject to an Internal Revenue Code (“IRC”) Section 382 annual limitation of approximately $6,487 per year. The Company obtained net operating loss carryforwards of approximately $11,526 and $8,763 as a result of the acquisitions of Community and Hometown, respectively, on March 1, 2016 which are also subject to IRC Section 382 limitations of approximately $1,722 and $507, respectively. On May 1, 2017, the Company completed its acquisition of Gateway and as a result obtained net operating loss carryforwards of approximately $5,407, which are subject to IRC Section 382 limitations of approximately $3,289. The Company obtained net operating loss carryforwards of approximately $22,529 and $14,003 as a result of the acquisitions of Sunshine and HCBF, respectively, on January 1, 2018 which are also subject to IRC Section 382 limitations of approximately $3,682 and $1,101, respectively. On September 1, 2018, the Company acquired approximately $3,780 of net operating loss carryforwards pursuant to its acquisition of Charter, however, these net operating loss carryforwards are less than the IRC Section 382 annual limitation of approximately $9,036. At December 31, 2018, total net operating losses approximate $71,483, which includes $19,653 from 2018. Effective January 1, 2018, net operating losses generated on January 1, 2018 and forward are no longer subject to a 20-year carryforward period and are carried indefinitely until fully utilized. Excluding the net operating losses not subject to expiration, the Company had approximately $51,830 of net operating loss carryforwards at December 31, 2018, which will begin to expire as follows: 2027 $ 2,418 2028 1,996 2029 11,826 2030 13,681 2031 7,246 2032 6,841 2033 7,063 2035 759 $ 51,830 As a result of the enactment of the Tax Act on December 22, 2017, the Company evaluated its deferred tax assets and deferred tax liabilities to account for the future impact of lower corporate tax rates on its deferred tax assets. The reduction in the federal corporate tax rate resulted in a one-time charge to the Company’s earnings and reduction to its net deferred tax assets of approximately $ 18,575 , which was recorded in 2017. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. In performing this analysis, the Company considers all evidence currently available, both positive and negative, in determining whether based on the weight of that evidence, it is more likely than not the deferred tax asset will be realized. Based on management’s analysis, it was determined that it is more likely than not that the net deferred tax asset, net of the one-time charge mentioned above, will be realized as of December 31, 2018 and 2017. The Company and its subsidiaries are subject to U.S. federal income tax as well as income tax of the states of Florida, Georgia, Alabama, California, Colorado, North Carolina and Tennessee. CSFL Insurance Corp. files a tax return in South Carolina. The Company is no longer subject to examination by taxing authorities for the years before 2015. The Company has not recorded any material interest or penalties on its income tax liabilities for the years 2018, 2017 and 2016. A reconciliation between the actual tax expense and the “expected” tax expense, computed by applying the U.S. federal corporate rate of 21 percent for 2018 and 35 percent for 2017 and 2016 is as follows: December 31, 2018 2017 2016 “Expected” tax expense $ 41,466 $ 38,246 $ 22,488 Tax exempt interest, net (3,177 ) (4,104 ) (2,364 ) Bank owned life insurance (1,167 ) (1,251 ) (825 ) State income taxes, net of federal income tax benefits 7,827 4,077 2,347 Stock based compensation 17 40 81 Merger and acquisition related expenses 610 1,049 388 Excess tax benefit from stock based compensation (5,095 ) (3,007 ) — Revaluation of net deferred tax asset due to change in federal income tax rate — 18,575 — Other, net 543 (145 ) (205 ) $ 41,024 $ 53,480 $ 21,910

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related-Party Transactions	(1 6 ) Related-Party Transactions Loans to principal officers, directors, and their affiliates during 2017 and 2016 were as follows: 2018 2017 Beginning balance $ 30,458 $ 26,515 New loans and advances on existing loans 39,183 21,753 Repayments (21,215 ) (17,810 ) Ending balance $ 48,426 $ 30,458 At December 31, 2018 and 2017 principal officers, directors, and their affiliates had $10,820 and $8,835, respectively, of available lines of credit. Deposits from principal officers, directors, and their affiliates at year-end 2018 and 2017 were approximately $6,739 and $4,777, respectively.

Regulatory Capital Matters

Regulatory Capital Matters	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Regulatory Capital Matters	(1 7 ) Regulatory Capital Matters The Company and the Bank are subject to various regulatory capital requirements administered by the federal banking agencies. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and the Bank must meet specific capital guidelines that involve quantitative measures of assets, liabilities and certain off-balance-sheet items as calculated under regulatory accounting practices. The capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s consolidated financial statements. The final rules implementing Basel Committee on Banking Supervision’s capital guidelines for U.S. banks (Basel III rules) became effective for the Company on January 1, 2015 with full compliance with all of the requirements being phased in over a multi-year schedule, and fully phased in by January 1, 2019. Under these rules, banks are required to maintain a minimum CET1 ratio of 4.5 %, a minimum Tier 1 capital to risk-weighted assets of 6 %, a total risk-based capital ratio of 8 %, and a minimum leverage capital ratio of 4 %. In addition, the rules require a capital conservation buffer of up to 2.5 % above each of CET1, tier 1, and total risk-based capital which must be met for a bank to be able to pay dividends, engage in share buybacks or make discretionary bonus payments to executive management without restriction. This capital conservation buffer is being phased in over a four-year period starting on January 1, 2016. The capital conservation buffer was % in 2018 and % as of January 1, 2019 . When fully implemented, a banking organization would need to maintain a CET1 capital ratio of at least 7 %, a total Tier 1 capital ratio of at least 8.5 % and a total risk-based capital ratio of at least 10.5 %. The net unrealized gain or loss on available for sale securities is not included in computing regulatory capital. Quantitative measures established by regulation to ensure capital adequacy require the Company and the Bank to maintain minimum amounts and ratios (set forth in the table below) of total capital, Tier I capital and CET1 (as defined in the regulations) to risk-weighted assets. Management believes, as of December 31, 2018, that the Company and the Bank meet all capital adequacy requirements to which they are subject. As of December 31, 2018 and 2017, the most recent notifications from the Office of Comptroller of the Currency (“OCC”) categorized the Bank as “well capitalized” under the regulatory framework for prompt corrective action. To be categorized as “well capitalized,” the Bank must maintain total risk-based, Tier I risk-based, common equity Tier 1 risk-based and Tier I leverage ratios as set forth in the table. There are no conditions or events since that notification that management believes have changed the institution’s category. A summary of actual, required, and capital levels necessary for capital adequacy purposes for the Company as of December 31, 2018 and 2017, are presented in the table below. The ratios for capital adequacy purposes do not include capital conservation buffer requirements. To be well capitalized under For capital prompt corrective Actual adequacy purposes action provision Amount Ratio Amount Ratio Amount Ratio December 31, 2018 Total capital (to risk weighted assets) $ 1,183,229 12.7% $ 745,543 >8.0% n/a n/a Tier 1 capital (to risk weighted assets) 1,143,459 12.3% 559,157 >6.0% n/a n/a Common equity tier 1 capital (to risk weighted assets) 1,104,959 11.9% 419,368 >4.5% n/a n/a Tier 1 capital (to average assets) 1,143,459 10.0% 455,561 >4.0% n/a n/a December 31, 2017 Total capital (to risk weighted assets) $ 682,175 12.6% $ 434,245 >8.0% n/a n/a Tier 1 capital (to risk weighted assets) 649,350 12.0% 325,684 >6.0% n/a n/a Common equity tier 1 capital (to risk weighted assets) 621,956 11.5% 244,263 >4.5% n/a n/a Tier 1 capital (to average assets) 649,350 9.8% 264,616 >4.0% n/a n/a A summary of actual, required, and capital levels necessary for capital adequacy purposes in the case of the Company’s subsidiary bank as of December 31, 2018 and 2017, are presented in the table below. The ratios for capital adequacy purposes do not include capital conservation buffer requirements. To be well capitalized under For capital prompt corrective Actual adequacy purposes action provision Amount Ratio Amount Ratio Amount Ratio December 31, 2018 Total capital (to risk weighted assets) $ 1,177,082 12.6% $ 745,003 >8.0% $ 931,254 >10.0% Tier 1 capital (to risk weighted assets) $ 1,137,315 12.2% 558,753 >6.0% 745,003 >8.0% Common equity tier 1 capital (to risk weighted assets) $ 1,137,315 12.2% 419,064 >4.5% 605,315 >6.5% Tier 1 capital (to average assets) $ 1,137,315 10.0% 455,515 >4.0% 569,394 >5.0% December 31, 2017 Total capital (to risk weighted assets) $ 654,018 12.2% $ 430,561 >8.0% $ 538,202 >10.0% Tier 1 capital (to risk weighted assets) 621,199 11.5% 322,921 >6.0% 430,561 >8.0% Common equity tier 1 capital (to risk weighted assets) 621,199 11.5% 242,191 >4.5% 349,831 >6.5% Tier 1 capital (to average assets) 621,199 9.4% 264,577 >4.0% 330,721 >5.0%

Dividends

Dividends	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Dividends	(1 8 ) Dividends The Company declared and paid cash dividends on its common stock of $35,906, $13,878 and $7,681 during the years ended December 31, 2018, 2017 and 2016, respectively. Banking regulations limit the amount of dividends that may be paid by the subsidiary banks to the Company without prior approval of the Bank’s regulatory agency. The Company received a $68,000 and $10,000 dividend from its subsidiary bank in 2018 and 2017, respectively. At December 31, 2018, dividends from the subsidiary bank available to be paid to the Company, without prior approval of the Bank’s regulatory agency, was $136,124, subject to the Bank meeting or exceeding regulatory capital requirements.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	(1 9 ) Stock-Based Compensation The Company assumed the obligations of Sunshine under Sunshine’s 2015 Equity Incentive Plan (“Sunshine Plan”) pursuant to the closing on January 1, 2018 by CenterState of the merger of Sunshine with and into CenterState. All of the Sunshine stock options awarded pursuant to the Sunshine Plan outstanding at the merger closing date were converted to stock options for 590,345 of the Company’s common shares with an average exercise price of $14.84 per share. At December 31, 2018, there were options outstanding for 16,020 shares of the Company’s common stock with an average exercise price of $15.88 per share and an average remaining contractual life of approximately 7.3 years. The Company assumed the obligations of HCBF under HCBF’s 2010 Amended and Restated Stock Incentive Plan (the “HCBF Plan”), pursuant to the closing on January 1, 2018 by CenterState of the merger of HCBF with and into CenterState. All of the HCBF stock options awarded pursuant to the HCBF Plan outstanding at the merger closing date were converted to stock options for 1,621,543 of the Company’s common shares with an average exercise price of $14.80 per share. At December 31, 2018, there were options outstanding for 145,616 shares of the Company’s common stock with an average exercise price of $15.06 per share and an average remaining contractual life of approximately 4.8 years. The Company assumed the obligations of Gateway under the Gateway Officers’ and Employees’ Stock Option Plan and the Gateway Directors’ Stock Option Plan (collectively, the “Gateway Plans”) pursuant to the closing on May 1, 2017 by CenterState of the merger of Gateway with and into CenterState. All of the Gateway stock options awarded pursuant to the Gateway Plans outstanding at the merger closing date were converted to stock options for 1,150,517 of the Company’s common shares with an average exercise price of $11.32 per share. At December 31, 2018, there were options outstanding for 341,425 shares of the Company’s common stock with an average exercise price of $10.70 per share and an average remaining contractual life of approximately 4.6 years. The Company assumed the obligations of GBI under the Gulfstream 2009 Stock Option Plan, the Gulfstream Officers’ and Employees’ Stock Option Plan and the Gulfstream Directors’ Stock Option Plan (collectively, the “Gulfstream Plans”) pursuant to the closing on January 17, 2014 by CenterState of the merger of Gulfstream with and into CenterState. All of the Gulfstream stock options awarded pursuant to the Gulfstream Plans outstanding at the merger closing date were converted to stock options for 774,104 of the Company’s common shares with an average exercise price of $6.99 per share. At December 31, 2018 there were options outstanding for 52,600 shares of the Company’s common stock with an average exercise price of $ per share and an average remaining contractual life of approximately 3. 6 years . On April 26, 2018, the Company’s shareholders approved the CenterState Bank Corporation 2018 Equity Incentive Plan (the “2018 Plan”). The 2018 Plan replaces the 2013 Plan discussed below. The 2018 Plan authorizes the issuance of up to 2,200,000 shares through the 2028 expiration of the plan. No more than $150 in grants of shares may be issued to any director in any one fiscal year. The Company’s Board of Directors froze the Company’s 2013 Equity Incentive Plan whereby no additional future grants and/or awards will be awarded pursuant to that plan effective with the shareholder approval of the 2018 Plan. During 2018 the Company did not grant any incentive stock options to its employees. The Company awarded 67,502 shares of Restricted Stock (“RSAs”) during 2018 with an average fair value of $26.77 per share at the date of grant. These restricted stock awards vest over periods ranging from two to five years. The Company awarded Performance Share Units (“PSUs”) during 2018 pursuant to the Company’s Long-Term Incentive Plan as described in the Company’s 2018 Proxy Statement. These PSUs will cliff vest on January 1, 2022. The units may be converted into common shares based upon the Company’s Total Shareholder Return compared to its peer group and the Company’s absolute earnings per share growth rate over a three-year period ending January 1, 2022. The range of the units that may vest in the future is a minimum of 0 and a maximum of 72,655 with an expected target of 48,435 shares. The Company also awarded 41,630 Restricted Share Units (“RSUs”) during 2018 with an average fair value of $26.60 per unit at the date of grant. The RSUs will vest at a rate of one third each January 1, 2020, 2021 and 2022. In addition, the Company issued 22,074 shares to non-employee directors in lieu of cash for director fees during 2018. At December 31, 2018, there were a total of 2,055,246 shares available for future grants pursuant to the 2018 Plan, assuming maximum future vesting of PSUs outstanding. On April 25, 2013, the Company’s shareholders approved the CenterState 2013 Equity Incentive Plan (the “2013 Plan”). The 2013 Plan replaced the 2007 Plan. The 2013 Plan authorized the issuance of up to 1,600,000 shares of the Company stock. In 2018, the 2013 Plan was frozen whereby no additional grants and/or awards were awarded pursuant to this plan subsequent to April 2018. On April 24, 2007, the Company’s shareholders approved the CenterState 2007 Equity Incentive Plan (the “2007 Plan”) and approved an amendment to the 2007 Plan on April 28, 2009. The 2007 Plan, as amended, authorized the issuance of up to 1,350,000 shares of the Company stock. In 2013, the 2007 Plan was frozen whereby no additional grants and/or awards were awarded pursuant to this plan subsequent to April 2013. The Company’s stock-based compensation consists of stock options, RSAs, RSUs and PSUs. During the twelve month period ended December 31, 2018, 2017 and 2016, the Company recognized total stock-based compensation expense as listed in the table below. 2018 2017 2016 Stock option expense $ 83 $ 115 $ 230 RSA expense 2,922 3,560 3,605 RSU Expense 538 287 169 PSU expense 650 624 419 Total stock-based compensation expense $ 4,193 $ 4,586 $ 4,423 There is no income tax benefit provided for in the Company’s tax provision for qualified incentive stock options. The Company receives a tax benefit when a non-qualified stock option is exercised. The total income tax benefit related to the exercise of non qualified stock options was approximately $5,373, $1,545 and $140 during the twelve-month periods ending December 31, 2018, 2017 and 2016, respectively. The Company provided an income tax benefit in its tax provision for RSA, RSU and PSU expenses of approximately $1,042, $1,725 and $1,617 during the twelve-month periods ending December 31, 2018, 2017 and 2016, respectively. As of December 31, 2018, the total remaining unrecognized compensation cost related to non-vested stock options was approximately $42 and will be recognized over the next 4 years. The weighted average period over which this expense is expected to be recognized is approximately 4.8 years . As of December 31, 2018, the total remaining unrecognized compensation cost related to non-vested RSAs, net of estimated forfeitures, was approximately $4,012 and will be recognized over the next 9 years. The weighted average period over which this expense is expected to be recognized is approximately 2.4 years. As of December 31, 2018, the total remaining unrecognized compensation cost related to non-vested PSUs, net of estimated forfeitures, was approximately $1,674 and will be recognized over the next 3 years. The weighted average period over which this expense is expected to be recognized is approximately 1.8 years. As of December 31, 2018 the total remaining unrecognized compensation cost related to non-vested RSUs, net of estimated forfeitures, was approximately $1,601 and will be recognized over the next 3 years. The weighted average period over which this expense is expected to be recognized is approximately 1.8 years. The Company did not grant any stock options during 2016, 2017 and 2018. However, the Company converted all outstanding Gateway stock options into CenterState options for 1,150,517 shares of common stock on the May 1, 2017 acquisition date pursuant to the Company’s agreement to acquire Gateway. The Company also converted all outstanding Sunshine and HCBF stock options into CenterState options for 590,345 and 1,621,543 shares of common stock, respectively, on the January 1, 2018 acquisition date pursuant to the Company’s respective agreements to acquire Sunshine and HCBF. The estimated fair value of options granted, or acquired in the case of Gateway, Sunshine and HCBF, during these periods were calculated as of the grant date, or the acquisition date in the case of Gateway, Sunshine and HCBF, using the Black-Scholes option-pricing model. The Company determined the expected life of the stock options using the simplified method approach allowed for plain-vanilla share options as described in SAB 107. The risk-free interest rate is based on the U.S. Treasury yield curve in effect as of the grant date. Expected volatility was determined using historical volatility. ASC 718 requires the recognition of stock-based compensation for the number of awards that are ultimately expected to vest. However, with the adoption of ASU 2016-09 in 2017, the Company made an entity-wide accounting policy election to account for forfeitures when they occur. The weighted-average estimated fair value of stock options granted, or acquired in the case of Sunshine and HCBF, during the twelve-month period ended December 31, 2018 was $14.81 per share. The table below present’s information related to stock option activity for the years ended December 31, 2018, 2017 and 2016: 2018 2017 2016 Total intrinsic value of stock options exercised $ 1,492 $ 8,039 $ 2,716 Net proceeds from stock options exercised $ 14,707 $ 6,715 $ 1,769 Gross income tax benefit from the exercise of stock options $ 5,373 $ 1,545 140 A summary of stock option activity for the years ended December 31, 2018, 2017 and 2016 is as follows: December 31, 2018 December 31, 2017 December 31, 2016 Weighted- Weighted- Weighted- Average Average Average Number of Exercise Number of Exercise Number of Exercise Options Price Options Price Options Price Outstanding, beginning of period 1,119,483 $ 11.26 623,490 $ 12.30 940,634 $ 11.73 Options assumed pursuant to acquisition of (note 1): Gateway — — 1,150,517 $ 11.32 — — HCBF 1,621,543 $ 14.80 — — — — Sunshine 590,345 $ 14.84 — — — — Exercised (1,793,339 ) $ 13.61 (598,039 ) $ 12.11 (229,583 ) $ 8.74 Forfeited (882,771 ) $ 15.37 (56,485 ) $ 15.00 (87,561 ) $ 15.51 Outstanding, end of period 655,261 $ 11.26 1,119,483 $ 11.26 623,490 $ 12.30 N ote 1: Pursuant to the Company’s respective agreements to acquire Gateway (on May 1, 2017), and Sunshine and HCBF (both on January 1, 2018), all outstanding Gateway, Sunshine and HCBF stock options were converted to CenterState stock options as of the acquisition date. Weighted- Weighted- Average Average Aggregate Number of Exercise Contractual Intrinsic Options Price Term Value Options outstanding, December 31, 2018 655,261 $ 11.26 4.2 years $ 6,412 Options fully vested and expected to vest, December 31, 2018 653,212 $ 11.27 4.2 years $ 6,381 Options exercisable, December 31, 2018 626,401 $ 11.37 4.3 years $ 6,051 At December 31, 2018 there were restricted stock awards (“RSAs”) for 390,366 shares of the Company’s common stock outstanding and not vested. Of this amount 50,600 restricted shares have been issued and included in the Company’s total common stock outstanding, but have not vested as of December 31, 2017. The remaining 339,766 represent common shares to be issued at the end of their respective vesting period. A summary of the RSA activity for the years ended December 31, 2018, 2017 and 2016 is presented in the table below. 2018 2017 2016 Number Number Weighted Number Number Weighted Number Number Weighted of RSAs of RSAs average of RSAs of RSAs average of RSAs of RSAs average underlying underlying Total fair value underlying underlying Total fair value underlying underlying Total fair value shares not shares number at grant shares not shares number at grant shares not shares number at grant issued issued of RSAs date issued issued of RSAs date issued issued of RSAs date Outstanding, beginning period 489,424 69,700 559,124 $ 15.89 572,064 127,901 699,965 $ 12.20 532,127 189,588 721,715 $ 10.79 Granted 67,502 — 67,502 $ 26.77 148,232 — 148,232 $ 24.94 262,934 — 262,934 $ 14.68 Vested (214,847 ) (19,100 ) (233,947 ) $ 13.65 (226,606 ) (58,201 ) (284,807 ) $ 11.52 (219,032 ) (60,087 ) (279,119 ) $ 10.88 Forfeited (2,313 ) — (2,313 ) $ 18.55 (4,266 ) — (4,266 ) $ 15.76 (3,965 ) (1,600 ) (5,565 ) $ 12.07 Outstanding, end of period 339,766 50,600 390,366 $ 19.10 489,424 69,700 559,124 $ 15.89 572,064 127,901 699,965 $ 12.20 In September 2014, the Company initiated a Long-Term Incentive Plan (“LTI”) that includes a Performance Share Unit (“PSU”) award that could be awarded in PSUs, which can eventually be converted to common stock, based on the Company’s relative Total Shareholder Return and absolute Earnings Per Share growth as compared to a peer group of similar companies selected by the Company’s Compensation Committee over a 39 month period beginning in September of each grant year. The Company awarded similar PSUs in 2015, 2016, 2017 and 2018. In 2018, a total of 157,020 PSUs were approved by the Company’s Compensation Committee pursuant to the 2014 LTI plan. The PSUs will be issued in the form of common stock at the end of the two-year mandatory hold period which ends in December 2019. The Company expects to recognize an expense of $307, $412, $687 and $1,134 over the vesting period for PSUs granted in 2015, 2016, 2017 and 2018, respectively. The expense recognized during 2018 for all PSUs awarded pursuant to all LTI plans was $520. In September 2016, the Company also awarded PSUs pursuant to a productive incentive plan to one of its divisions that could eventually be converted to the Company’s common stock based upon the division’s financial performance over three and four year periods ending August 31, 2019 and 2020, respectively. The Company expects to recognize a total expense of $192 during the performance periods. The expense recognized during 2018 was $130. The Company awarded RSUs during September 2015, 2016, 2017 and 2018 pursuant to its LTI plans as mentioned above that could eventually be converted into the Company’s common stock. The Company expects to recognize an expense of $356, $442, $720 and $1,107 for the RSUs awarded in 2015, 2016, 2017 and 2018, respectively. Generally, the RSUs will vest at a rate of one third each January 1 st December 31, 2018 December 31, 2017 December 31, 2016 Weighted Weighted Weighted average average average fair value fair value fair value Number of at grant Number of at grant Number of at grant Units date Units date Units date Outstanding, beginning of period 86,817 $ 17.00 54,376 $ 14.00 29,092 $ 12.22 Granted 41,630 26.60 32,441 22.19 28,725 15.37 Vested and issued — — — — (3,441 ) 12.22 Forfeited — — — — — — Outstanding, end of period 128,447 $ 20.00 86,817 $ 17.00 54,376 $ 14.00

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	( 20 ) Employee Benefit Plan Substantially all of the Company’s employees are covered under its 401(k) defined contribution retirement plan. Employees are eligible to participate in the plan after completing six months of continuous employment. The Company contributes an amount equal to a certain percentage of the employees’ contributions based on the discretion of the Board of Directors. In addition, the Company may also make additional contributions to the plan each year, subject to profitability and other factors, and based solely on the discretion of the Board of Directors. For the years ended December 31, 2018, 2017 and 2016, the Company’s contributions to the plan were $3,444, $2,249 and $1,849, respectively, which are included in Salary, Wages and Employee Benefits on the Consolidated Statements of Income and Comprehensive Income. The Company has since amended its 401(k) defined contribution retirement plan’s participation eligibility requirement to the first month following the date of employment effective January 1, 2019. In 2008, the Company entered into a salary continuation agreement with its then chief executive officer. Five additional Company executive officers entered into salary continuation agreements during 2010. In 2007, an additional four pre-existing salary continuation agreements with certain Valrico State Bank’s executive officers were assumed as part of the acquisition. In 2018, the Company assumed pre-existing supplemental executive retirement plan agreements pursuant to the acquisition of Charter. The plans are nonqualified deferred compensation arrangements that are designed to provide supplemental retirement income benefits to participants. The Company expensed $641, $568 and $609 for the accrual of future salary continuation benefits in 2018, 2017 and 2016, respectively. Other liabilities included salary continuation benefits payable of $7,966, $4,834 and $4,211 at December 31, 2017, 2016 and 2015, respectively. In 2007, the Company entered into deferred compensation arrangements, through Rabbi Trust agreements, with two Valrico State Bank’s executive officers pursuant to the acquisition. The Rabbi Trust asset is included in other assets, and the related deferred compensation payable is included in other liabilities. In 2018, one of the executive officers retired and received the applicable funds from the agreement. The Rabbi Trust asset and the related deferred compensation payable at December 31, 2018, 2017 and 2016 were $307, $1,761 and $1,560, respectively. Earnings from the Rabbi Trust increase the asset and increase the deferred compensation payable. Losses from the Rabbi Trust decrease the asset and decrease the deferred compensation payable. There was no net income statement effect other than the administration expenses of the Trust which approximates $5 per year.

Parent Company Only Financial S

Parent Company Only Financial Statements	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Parent Company Only Financial Statements	(2 1 ) Parent Company Only Financial Statements Condensed financial statements of CenterState Bank Corporation (parent company only) follow: Condensed Balance Sheets December 31, 2018 and 2017 Assets: 2018 2017 Cash and due from banks $ 1,338 $ 1,569 Inter-company receivable from bank subsidiary 2,340 840 Investment in wholly-owned bank subsidiary 1,999,963 903,882 Investment in other wholly-owned subsidiary 2,761 1,951 Prepaid expenses and other assets 10,506 49,011 Total assets $ 2,016,908 $ 957,253 Liabilities: Accounts payable and accrued expenses $ 2,149 $ 6,311 Other borrowings 11,000 20,000 Corporate debentures 32,415 26,192 Total liabilities 45,564 52,503 Stockholders’ Equity: Common stock 957 602 Additional paid-in capital 1,699,031 737,905 Retained earnings 293,777 173,248 Accumulated other comprehensive income (22,421 ) (7,005 ) Total stockholders’ equity 1,971,344 904,750 Total liabilities and stockholders' equity $ 2,016,908 $ 957,253 Condensed Statements of Operations Years ended December 31, 2018, 2017 and 2016 2018 2017 2016 Dividend income $ 68,000 $ 10,000 $ 58,000 Other income 8 — 308 Interest expense (3,415 ) (1,363 ) (1,159 ) Operating expenses (3,988 ) (3,960 ) (3,869 ) Income before equity in undistributed income of subsidiaries 60,605 4,677 53,280 Equity in undistributed income (losses) of subsidiaries 88,532 48,760 (12,736 ) Net income before income tax benefit 149,137 53,437 40,544 Income tax benefit (7,298 ) (2,358 ) (1,797 ) Net income $ 156,435 $ 55,795 $ 42,341 Condensed Statements of Cash Flows Years ended December 31, 2018, 2017 and 2016 2018 2017 2016 Cash flows from operating activities: Net income $ 156,435 $ 55,795 $ 42,341 Adjustments to reconcile net income to net cash used in operating activities: Undistributed net (earnings) losses of subsidiaries (88,532 ) (48,760 ) 70,736 Increase in payables and accrued expenses (13,385 ) 463 (25 ) Gain on extinguishment of debt — — (308 ) (Increase) decrease in other assets 3,998 (40,369 ) 84 Stock based compensation expense — 1,048 1,001 Net cash flows provided by (used in) operating activities 58,516 (31,823 ) 113,829 Cash flows from investing activities: Inter-company receivables from subsidiary bank (473 ) 25,145 (58,241 ) Net cash from bank acquisitions (36,037 ) (42,601 ) (38,918 ) Investment in subsidiaries — (25,000 ) 450 Cash payments to shareholders 19,339 (90 ) 39 Net cash flows used in investing activities (17,171 ) (42,546 ) (96,670 ) Cash flows from financing activities: Stock options exercised 14,707 6,715 1,769 Stock repurchase (1,027 ) (1,131 ) (962 ) Stock issuance 650 — — Extinguishment of debt — — (8,680 ) (Decrease) increase in other borrowings (20,000 ) 20,000 (650 ) Proceeds from stock offering, net of offering costs — 63,262 — Dividends paid to shareholders (35,906 ) (13,878 ) (7,681 ) Net cash flows (used in) provided by financing activities (41,576 ) 74,968 (16,204 ) Net increase (decrease) in cash and cash equivalents (231 ) 599 955 Cash and cash equivalents at beginning of year 1,569 970 15 Cash and cash equivalents at end of year $ 1,338 $ 1,569 $ 970

Credit Commitments

Credit Commitments	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Credit Commitments	(2 2 ) Credit Commitments The Company has outstanding at any time a significant number of commitments to extend credit. These arrangements are subject to strict credit control assessments and each customer’s credit worthiness is evaluated on a case-by-case basis. A summary of commitments to extend credit and standby letters of credit written at December 31, 2018 and 2017, are as follows: December 31, 2018 2017 Standby letters of credit $ 28,964 $ 15,740 Available lines of credit 1,514,359 824,958 Unfunded loan commitments – fixed 153,680 140,750 Unfunded loan commitments – variable 65,880 35,814 Commitments to make loans are generally made for periods of 30 days or less. At December 31, 2018, the fixed rate loan commitments have interest rates ranging from 3.27% to 8.35% and maturities ranging from 1 year to 20 years. Because many commitments expire without being funded in whole or part, the contract amounts are not estimates of future cash flows. Credit risk represents the accounting loss that would be recognized at the reporting date if counterparties failed completely to perform as contracted. The credit risk amounts are equal to the contractual amounts, assuming that the amounts are fully advanced and that the collateral or other security is of no value. The Company’s policy is to require customers to provide collateral prior to the disbursement of approved loans. The amount of collateral obtained, if it is deemed necessary by the Company upon extension of credit, is based on management’s credit evaluation of the counterparty. Collateral held varies but may include accounts receivable, inventory, real estate and income providing commercial properties. Standby letters of credit are contractual commitments issued by the Company to guarantee the performance of a customer to a third party. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. Outstanding commitments are deemed to approximate fair value due to the variable nature of the interest rates involved and the short-term nature of the commitments.

Concentrations of Credit Risk

Concentrations of Credit Risk	12 Months Ended
	Dec. 31, 2018
Risks And Uncertainties [Abstract]
Concentrations of Credit Risk	(2 3 ) Concentrations of Credit Risk Most of the Company’s business activity is with customers located throughout Southeastern United States including Florida, Georgia and Alabama. The majority of commercial and mortgage loans are granted to customers doing business or residing in these areas. Generally, commercial loans are secured by real estate, and mortgage loans are secured by either first or second mortgages on residential or commercial property. As of December 31, 2018, substantially all of the Company’s loan portfolio was secured. Although the Company has a diversified loan portfolio, a substantial portion of its debtors’ ability to honor their contracts is dependent upon the economy of those areas listed above. The Company does not have significant exposure to any individual customer or counterparty.

Basic and Diluted Earnings Per

Basic and Diluted Earnings Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Basic and Diluted Earnings Per Share	(2 4 ) Basic and Diluted Earnings Per Share The two-class method is used in the calculation of basic and diluted earnings per share. Under the two-class method, earnings available to common shareholders for the period are allocated between common shareholders and participating securities according to dividends declared (or accumulated) and participation rights in undistributed earnings. There were no anti-dilutive stock options for the years ending December 31, 2018 and 2017. There were 24,500 stock options that were not considered in computing diluted earnings per common share because they were anti-dilutive during the years ending December 31, 2016. The following table presents the factors used in the earnings per share computations for the periods indicated. 2018 2017 2016 Basic Net income available to common shareholders $ 156,435 $ 55,795 $ 42,341 Less: Earnings allocated to participating securities (116 ) (120 ) (163 ) Net income allocated to common shareholders $ 156,319 $ 55,675 $ 42,178 Weighted average common shares outstanding including participating securities 87,707,196 57,368,322 47,592,500 Less: Participating securities (1) (65,976 ) (123,624 ) (183,358 ) Average shares 87,641,220 57,244,698 47,409,142 Basic earnings per common share $ 1.78 $ 0.97 $ 0.89 Diluted Net income available to common shareholders $ 156,319 $ 55,675 $ 42,178 Weighted average common shares outstanding for basic earnings per common share 87,641,220 57,244,698 47,409,142 Add: Dilutive effects of stock based compensation awards 1,117,633 1,096,115 782,381 Average shares and dilutive potential common shares 88,758,853 58,340,813 48,191,523 Dilutive earnings per common share $ 1.76 $ 0.95 $ 0.88 Note 1. Participating securities are restricted stock awards whereby the stock certificates have been issued, are included in outstanding shares, receive dividends and can be voted, but have not vested.

Reportable Segments

Reportable Segments	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Reportable Segments	(2 5 ) Reportable Segments The Company’s reportable segments represent the distinct product lines the Company offers and are viewed separately for strategic planning purposes by management. The tables below are reconciliations of the reportable segment revenues, expenses, and profit as viewed by management to the Company’s consolidated total for the year ending December 31, 2018, 2017 and 2016. Year ending December 31, 2018 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 445,688 $ 14,944 $ — — $ 460,632 Interest expense (36,853 ) $ (7,282 ) (3,415 ) — (47,550 ) Net interest income (expense) 408,835 $ 7,662 (3,415 ) — 413,082 Provision for loan losses (7,914 ) $ (369 ) — — (8,283 ) Non-interest income 71,731 $ 33,388 8 — 105,127 Non-interest expense (286,191 ) $ (22,288 ) (3,988 ) — (312,467 ) Net income (loss) before taxes 186,461 $ 18,393 (7,395 ) — 197,459 Income tax (provision) benefit (43,662 ) (4,660 ) 7,298 — (41,024 ) Net income (loss) $ 142,799 $ 13,733 $ (97 ) $ — $ 156,435 Total assets $ 11,769,734 $ 561,885 $ 2,016,908 $ (2,010,939 ) $ 12,337,588 Year ending December 31, 2017 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 240,583 $ 10,743 $ — — $ 251,326 Interest expense (11,431 ) (2,989 ) (1,363 ) — (15,783 ) Net interest income (expense) 229,152 7,754 (1,363 ) — 235,543 Provision for loan losses (5,037 ) 79 — — (4,958 ) Non-interest income 36,834 28,341 — — 65,175 Non-interest expense (161,946 ) (20,579 ) (3,960 ) — (186,485 ) Net income (loss) before taxes 99,003 15,595 (5,323 ) — 109,275 Income tax (provision) benefit (49,823 ) (6,015 ) 2,358 — (53,480 ) Net income (loss) $ 49,180 $ 9,580 $ (2,965 ) $ — $ 55,795 Total assets $ 6,572,636 $ 506,234 $ 957,253 $ (912,148 ) $ 7,123,975 Year ending December 31, 2016 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 180,696 $ 7,969 $ — — $ 188,665 Interest expense (7,044 ) (1,137 ) (1,159 ) — (9,340 ) Net interest income 173,652 6,832 (1,159 ) — 179,325 Provision for loan losses (4,938 ) (24 ) — — (4,962 ) Non-interest income 30,376 33,685 308 — 64,369 Non-interest expense (147,228 ) (23,384 ) (3,869 ) — (174,481 ) Net income before taxes 51,862 17,109 (4,720 ) — 64,251 Income tax (provision) benefit (17,107 ) (6,600 ) 1,797 — (21,910 ) Net income (loss) $ 34,755 $ 10,509 $ (2,923 ) $ — $ 42,341 Total assets $ 4,676,375 $ 397,323 $ 584,572 $ (579,711 ) $ 5,078,559 Commercial and retail banking : The Company’s primary business is commercial and retail banking. Currently, the Company operates primarily through the Bank providing traditional retail, commercial, mortgage, wealth management and SBA services throughout its Florida, Georgia and Alabama branch network and customer relationships in neighboring states. Correspondent banking and capital markets division Corporate overhead and administration

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Business Combinations	(26) Business C Acquisition of Platinum Bank Holding Company On April 1, 2017, the Company completed its acquisition of Platinum Bank Holding Company (“Platinum”) whereby Platinum merged with and into the Company. Pursuant to and simultaneously with the merger of Platinum with and into the Company, Platinum’s wholly owned subsidiary bank, Platinum Bank merged with and into the Company’s subsidiary bank, CenterState Bank, N.A. The Company’s primary reasons for the transaction were to further solidify its market share in the Central Florida markets and expand its customer base to enhance deposit fee income and leverage operating cost through economies of scale. The acquisition increased the Company’s total assets and total deposits by approximately 14% and 13%, respectively, as compared with the balances at December 31, 2016, and is expected to positively affect the Company’s operating results to the extent the Company earns more from interest earning assets than it pays in interest on its interest bearing liabilities. No acquisition costs related to the Platinum acquisition were incurred during the twelve-month period ending December 31, 2018. During the twelve-month periods ending December 31, 2017 and 2016, the Company incurred approximately $3,924 and $186 of acquisition costs related to this transaction, respectively. These acquisition costs are reported in Merger Related Expenses on the Company’s Consolidated Statements of Income and Comprehensive Income. The acquisition was accounted for under the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations The Company acquired 100% of the outstanding common stock of Platinum. The purchase price consisted of both cash and stock. Each share of Platinum common stock was exchanged for $7.60 cash and 3.7832 shares of the Company’s common stock. Based on the closing price of the Company’s common stock on March 31, 2017, the resulting purchase price was $119,431. The table below summarizes the purchase price calculation. Number of shares of Platinum common stock exchanged for CenterState common stock 1,131,134 Per share exchange ratio 3.7832 Number of shares of CenterState common stock less 51 of fractional shares 4,279,255 CenterState common stock price per share on March 31, 2017 $ 25.90 Fair value of CenterState common stock issued $ 110,833 Total Platinum common shares 1,131,134 Cash consideration each Platinum share was entitled to receive $ 7.60 Total cash consideration, not including cash for fractional shares $ 8,597 Total stock consideration $ 110,833 Total cash consideration, plus $1 for 51 of fractional shares $ 8,598 Total purchase price $ 119,431 The list below summarizes the estimates of the fair value of the assets purchased, including goodwill, and liabilities assumed as of the April 1, 2017 purchase date. April 1, 2017 Assets: Cash and cash equivalents $ 106,537 Loans, held for investment 442,366 Purchased credit impaired loans 12,218 Investments 28,873 Accrued interest receivable 1,216 Branch real estate 9,600 Furniture and fixtures 402 Bank property held for sale 4,382 FHLB stock 2,220 Other repossessed real estate owned 272 Core deposit intangible 3,992 Goodwill 73,829 Deferred tax asset 227 Other assets 29 Total assets acquired $ 686,163 Liabilities: Deposits $ 520,423 Federal Home Loan Bank advances 40,546 Securities sold under agreement to repurchase 5,569 Accrued interest payable 94 Other liabilities 100 Total liabilities assumed $ 566,732 In the acquisition, the Company acquired $454,584 of loans at fair value, net of $8,980, or 1.9%, estimated discount to the outstanding principal balance, representing 13.3% of the Company’s total loans at December 31, 2016. Of the total loans acquired, management identified $12,218 with credit deficiencies. All loans that were on non-accrual status, impaired loans including TDRs and other substandard loans were considered by management to be credit impaired and are accounted for pursuant to ASC Topic 310-30. The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of April 1, 2017 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 18,811 Non-accretable difference (4,639 ) Cash flows expected to be collected 14,172 Accretable yield (1,954 ) Total purchased credit-impaired loans acquired $ 12,218 The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Balance Fair Value Loans: Single family residential real estate $ 37,206 $ 37,419 Commercial real estate 262,612 259,727 Construction/development/land 47,675 46,618 Commercial loans 96,587 95,701 Consumer and other loans 2,954 2,901 Purchased credit-impaired 16,530 12,218 Total earning assets $ 463,564 $ 454,584 In its assumption of the deposit liabilities, the Company believed the deposits assumed from the acquisition have an intangible value. The Company applied ASC Topic 805, which prescribes the accounting for goodwill and other intangible assets such as core deposit intangibles, in a business combination. The Company determined the estimated fair value of the core deposit intangible asset totaled $3,992, Acquisition of Gateway Financial Holdings of Florida, Inc. On May 1, 2017, the Company completed its acquisition of Gateway Financial Holdings of Florida, Inc. (“Gateway”) Gateway merged with and into the Company. Pursuant to and simultaneously with the merger of Gateway with and into the Company, Gateway’s three subsidiary banks, Gateway Bank of Florida, Gateway Bank of Central Florida and Gateway Bank of Southwest Florida, merged with and into the Company’s subsidiary bank, CenterState Bank, N.A The Company’s primary reasons for the transaction were to expand its market share in the Central Florida market, together with its acquisition of Platinum as described above, and expand its customer base to enhance deposit fee income and leverage operating cost through economies of scale. The acquisition increased the Company’s total assets and total deposits by approximately 19% and 17%, respectively, as compared with the balances at December 31, 2016, and is expected to positively affect the Company’s operating results to the extent the Company earns more from interest earning assets than it pays in interest on its interest bearing liabilities. During the twelve-month periods ending December 31, 2018, 2017 and 2016, the Company incurred approximately $149 , $6,203 and $11 of acquisition costs related to this transaction, respectively. These acquisition costs are reported in Merger Related Expenses on the Company’s Consolidated Statements of Income and Comprehensive Income. The acquisition was accounted for under the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations The Company acquired 100 % of the outstanding common stock of Gateway. The purchase price consisted of both cash and stock. Each share of Gateway common stock was either exchanged for $ 18.00 or $ 0.95 shares of the Company’s common stock. In addition, the Company assumed Gateway’s stock options, which were converted to the Company’s stock options. Based on the closing price of the Company’s common stock on April 30, 2017, the resulting purchase price was $ 157,372 . The table below summarizes the purchase price calculation. Number of shares of Gateway common stock outstanding at April 30, 2017 5,463,764 Gateway preferred shares that converted to Gateway common shares upon a change in control 919,236 Total Gateway common shares including conversion of preferred shares 6,383,000 Number of shares of Gateway common shares exchanged for CenterState common stock 4,468,100 Per share exchange ratio 0.95 Number of shares of CenterState common stock less 254 of fractional shares 4,244,441 CenterState common stock price per share on April 30, 2017 $ 25.23 Fair value of CenterState common stock issued $ 107,087 Number of shares of Gateway common shares exchanged for cash 1,914,900 Cash consideration each Gateway share is entitled to receive $ 18.00 Total cash consideration, not including cash for fractional shares $ 34,468 Total stock consideration $ 107,087 Total cash consideration plus $6 for 254 of fractional shares $ 34,474 Total consideration paid to Gateway common shareholders $ 141,561 Fair value of Gateway stock options converted to CenterState stock options $ 15,811 Total purchase price $ 157,372 The list below summarizes the preliminary estimates of the fair value of the assets purchased, including goodwill, and liabilities assumed as of the May 1, 2017 purchase date. May 1, 2017 Assets: Cash and cash equivalents $ 23,065 Loans, held for investment 560,413 Purchased credit impaired loans 7,827 Investments 231,951 Accrued interest receivable 2,422 Branch real estate 18,160 Furniture and fixtures 702 Bank property held for sale 1,087 FHLB and FRB stock 4,640 Other repossessed real estate owned 134 Bank owned life insurance 15,475 Servicing asset 271 Core deposit intangible 8,432 Goodwill 77,826 Deferred tax asset 7,246 Other assets 1,217 Total assets acquired $ 960,868 Liabilities: Deposits $ 708,209 Federal Home Loan Bank advances 90,598 Federal funds purchased 3,588 Accrued interest payable 304 Other liabilities 797 Total liabilities assumed $ 803,496 In the acquisition, the Company acquired $568,240 of loans at fair value, net of $9,479, or 1.6%, estimated discount to the outstanding principal balance, representing 16.6% of the Company’s total loans at December 31, 2016. Of the total loans acquired, management identified $ 7,827 with credit deficiencies. All loans that were on non-accrual status, impaired loans including TDRs and other substandard loans were considered by management to be credit impaired and are accounted for pursuant to ASC Topic 310-30. The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of May 1, 2017 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 12,523 Non-accretable difference (2,465 ) Cash flows expected to be collected 10,058 Accretable yield (2,231 ) Total purchased credit-impaired loans acquired $ 7,827 The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Fair Balance Value Loans: Single family residential real estate $ 142,881 $ 142,468 Commercial real estate 321,262 317,578 Construction/development/land 47,727 46,489 Commercial loans 46,953 46,274 Consumer and other loans 7,803 7,604 Purchased credit-impaired 11,093 7,827 Total earning assets $ 577,719 $ 568,240 In its assumption of the deposit liabilities, the Company believed the deposits assumed from the acquisition have an intangible value. The Company applied ASC Topic 805, which prescribes the accounting for goodwill and other intangible assets such as core deposit intangibles, in a business combination. The Company determined the estimated fair value of the core deposit intangible asset totaled $8,432, which will be amortized utilizing an accelerated amortization method over an estimated economic life not to exceed ten years. In determining the valuation amount, deposits were analyzed based on factors such as type of deposit, deposit retention, interest rates and age of deposit relationships. Acquisition of Sunshine Bancorp, Inc. On January 1, 2018, the Company completed its acquisition of Sunshine Bancorp, Inc. (“Sunshine”) whereby Sunshine merged with and into the Company. Pursuant to and simultaneously with the merger of Sunshine with and into the Company, Sunshine’s wholly owned subsidiary bank, Sunshine Bank merged with and into the Company’s subsidiary bank, CenterState Bank, N.A. The Company’s primary reasons for the transaction were to further solidify its market share in the Florida market and expand its customer base to enhance deposit fee income and leverage operating cost through economies of scale. The acquisition increased the Company’s total assets and total deposits by approximately 14% and 13%, respectively, as compared with the balances at December 31, 2017, and is expected to positively affect the Company’s operating results to the extent the Company earns more from interest earning assets than it pays in interest on its interest bearing liabilities. During the twelve-month periods ending December 31, 2018 and 2017, the Company incurred approximately $10,474 and $859, respectively, of acquisition costs related to this transaction. A portion of these merger expenses reduced goodwill by $4,114, net of income taxes of $1,397 The acquisition was accounted for under the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations The Company acquired 100% of the outstanding common stock of Sunshine. The purchase price consisted of stock plus cash in lieu of fractional shares. Each share of Sunshine common stock was exchanged for 0.89 shares of the Company’s common stock. Based on the closing price of the Company’s common stock on December 29, 2017, the resulting purchase price was $187,852. The table below summarizes the purchase price calculation. Number of shares of Sunshine common stock outstanding at December 31, 2017 7,922,479 Per share exchange ratio 0.89 Number of shares of CenterState common stock less 361 of fractional shares 7,050,645 CenterState common stock price per share on December 29, 2017 $ 25.73 Fair value of CenterState common stock issued $ 181,413 Cash consideration paid for 361 of fractional shares 7 Total consideration to be paid to Sunshine common shareholders $ 181,420 Fair value of Sunshine stock options converted to CenterState stock options 6,432 Total Purchase Price for Sunshine $ 187,852 The list below summarizes the fair value of the assets purchased, including goodwill, and liabilities assumed as of the January 1, 2018 purchase date. January 1, 2018 Assets: Cash and cash equivalents $ 47,056 Loans, held for investment 676,090 Purchased credit impaired loans 8,232 Loans held for sale 430 Investments 93,006 Accrued interest receivable 2,170 Branch real estate 9,375 Furniture and fixtures 916 Bank property held for sale 9,503 FHLB stock 4,875 Bank owned life insurance 23,101 Core deposit intangible 8,525 Goodwill 114,228 Deferred tax asset 11,890 Other assets 5,915 Total assets acquired $ 1,015,312 Liabilities: Deposits $ 719,039 Federal Home Loan Bank advances 95,001 Securities sold under agreement to repurchase 353 Subordinated notes 11,000 Accrued interest payable 457 Other liabilities 1,610 Total liabilities assumed $ 827,460 In the acquisition, the Company acquired $684,322 of loans at fair value, net of $22,657, or 3.2%, estimated discount to the outstanding principal balance, representing 14.3% of the Company’s total loans at December 31, 2017. Of the total loans acquired, management identified $8,232 with credit deficiencies. All loans that were on non-accrual status, impaired loans including TDRs and other substandard loans were considered by management to be credit impaired and are accounted for pursuant to ASC Topic 310-30. The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of January 1, 2018 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 21,598 Non-accretable difference (12,213 ) Cash flows expected to be collected 9,385 Accretable yield (1,153 ) Total purchased credit-impaired loans acquired $ 8,232 The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Fair Balance Value Loans: Single family residential real estate $ 148,342 $ 146,057 Commercial real estate 375,377 371,323 Construction/development/land 58,530 57,331 Commercial loans 104,811 99,650 Consumer and other loans 1,770 1,729 Purchased credit-impaired 18,149 8,232 Total earning assets $ 706,979 $ 684,322 In its assumption of the deposit liabilities, the Company believed the deposits assumed from the acquisition have an intangible value. The Company applied ASC Topic 805, which prescribes the accounting for goodwill and other intangible assets such as core deposit intangibles, in a business combination. The Company determined the estimated fair value of the core deposit intangible asset totaled $8,525, Acquisition of HCBF Holding Company, Inc. On January 1, 2018, the Company completed its acquisition of HCBF Holding Company, Inc. (“HCBF”) whereby HCBF merged with and into the Company. Pursuant to and simultaneously with the merger of HCBF with and into the Company, HCBF’s wholly owned subsidiary bank, Harbor Bank merged with and into the Company’s subsidiary bank, CenterState Bank, N.A. The Company’s primary reasons for the transaction were to further solidify its market share in the Florida market and expand its customer base to enhance deposit fee income and leverage operating cost through economies of scale. The acquisition increased the Company’s total assets and total deposits by approximately 33% and 32%, respectively, as compared with the balances at December 31, 2017, and is expected to positively affect the Company’s operating results to the extent the Company earns more from interest earning assets than it pays in interest on its interest bearing liabilities. During the twelve-month periods ending December 31, 2018 and 2017, the Company incurred approximately $12,302 and $2,060, respectively, of acquisition costs related to this transaction. These acquisition costs are reported in Merger Related Expenses on the Company’s Consolidated Statements of Income and Comprehensive Income. The acquisition was accounted for under the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations The Company acquired 100% of the outstanding common stock of HCBF. The purchase price consisted of both cash and stock. Each share of HCBF common stock was exchanged for $1.925 cash and 0.675 shares of the Company’s common stock. Based on the closing price of the Company’s common stock on December 29, 2017, the resulting purchase price was $448,236. The table below summarizes the purchase price calculation. Number of shares of HCBF common stock outstanding at December 31, 2017 22,299,082 Per share exchange ratio 0.675 Number of shares of CenterState common stock less 241 of fractional shares 15,051,639 CenterState common stock price per share on December 29, 2017 $ 25.73 Fair value of CenterState common stock issued $ 387,279 Number of shares of HCBF common stock outstanding at December 31, 2017 22,299,082 Cash consideration each HCBF share is entitled to receive $ 1.925 Total Cash Consideration plus $6 for 241 of fractional shares $ 42,932 Total Stock Consideration $ 387,279 Total Cash Consideration 42,932 Total consideration to be paid to HCBF common shareholders $ 430,211 Fair value of HCBF stock options converted to CenterState stock options $ 18,025 Total Purchase Price for HCBF $ 448,236 The list below summarizes the fair value of the assets purchased, including goodwill, and liabilities assumed as of the January 1, 2018 purchase date. January 1, 2018 Assets: Cash and cash equivalents $ 77,176 Loans, held for investment 1,290,004 Purchased credit impaired loans 36,031 Loans held for sale 5,694 Investments 585,297 Accrued interest receivable 5,847 Branch real estate 34,035 Furniture and fixtures 3,571 Bank property held for sale 14,140 FHLB and other stock 9,488 Bank owned life insurance 39,089 Other real estate owned 5,144 Core deposit intangible 23,625 Goodwill 233,321 Deferred tax asset 14,684 Other assets 1,923 Total assets acquired $ 2,379,069 Liabilities: Deposits $ 1,755,155 Federal Home Loan Bank advances 157,919 Corporate debentures 5,872 Accrued interest payable 478 Other liabilities 11,409 Total liabilities assumed $ 1,930,833 In the acquisition, the Company acquired $1,326,035 of loans at fair value, net of $40,438, or 3.0%, estimated discount to the outstanding principal balance, representing 27.8% of the Company’s total loans at December 31, 2017. Of the total loans acquired, management identified $36,031 with credit deficiencies. All loans that were on non-accrual status, impaired loans including TDRs and other substandard loans were considered by management to be credit impaired and are accounted for pursuant to ASC Topic 310-30. The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of January 1, 2018 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 67,107 Non-accretable difference (25,951 ) Cash flows expected to be collected 41,156 Accretable yield (5,125 ) Total purchased credit-impaired loans acquired $ 36,031 The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Fair Balance Value Loans: Single family residential real estate $ 370,611 $ 363,559 Commercial real estate 636,517 627,900 Construction/development/land 149,547 146,639 Commercial loans 113,818 110,630 Consumer and other loans 41,660 41,276 Purchased credit-impaired 54,320 36,031 Total earning assets $ 1,366,473 $ 1,326,035 In its assumption of the deposit liabilities, the Company believed the deposits assumed from the acquisition have an intangible value. The Company applied ASC Topic 805, which prescribes the accounting for goodwill and other intangible assets such as core deposit intangibles, in a business combination. The Company determined the estimated fair value of the core deposit intangible asset totaled $23,625, Acquisition of Charter Financial Corporation On September 1, 2018, the Company completed its acquisition of Charter Financial Corporation (“Charter”) whereby Charter merged with and into the Company. Pursuant to and simultaneously with the merger of Charter with and into the Company, Charter’s wholly owned subsidiary bank, CharterBank, merged with and into the Company’s subsidiary bank, CenterState Bank, N.A. The Company’s primary reasons for the transaction were to expand its franchise into Georgia and Alabama, further solidify its market share in the Florida market and expand its customer base to enhance deposit fee income and leverage operating cost through economies of scale. The acquisition increased the Company’s total assets and total deposits by approximately 24% The acquisition was accounted for under the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations Fair value estimates on loans are deemed preliminary due to appraisals, other borrower financial information, and pending final reports from loan valuation specialists. The Company acquired 100% of the outstanding common stock of Charter. The purchase price consisted of both cash and stock. Each share of Charter common stock was exchanged for $2.30 cash and 0.738 shares of the Company’s common stock. Based on the closing price of the Company’s common stock on August 31, 2018, the resulting purchase price was $389,476. The table below summarizes the purchase price calculation. Number of shares of Charter common stock outstanding at August 31, 2018 15,480,776 Per share exchange ratio 0.738 Number of shares of CenterState common stock less 599 of fractional shares 11,424,214 CenterState common stock price per share on August 31, 2018 $ 30.62 Fair value of CenterState common stock issued $ 349,809 Number of shares of Charter common stock outstanding at August 31, 2018 15,480,776 Cash consideration each Charter share is entitled to receive $ 2.300 Total Cash Consideration plus $17 for 599 of fractional shares $ 35,624 Total Stock Consideration $ 349,809 Total Cash Consideration 35,624 Total consideration to be paid to Charter common shareholders $ 385,433 Cash out of Charter stock options 4,043 Total Purchase Price for Charter $ 389,476 The list below summarizes the fair value of the assets purchased, including goodwill, and liabilities assumed as of the September 1, 2018 purchase date. September 1, 2018 Assets: Cash and cash equivalents $ 184,020 Loans, held for investment 1,130,240 Purchased credit impaired loans 11,432 Loans held for sale 2,835 Investments 73,808 Accrued interest receivable 3,684 Branch real estate 27,930 Furniture and fixtures 1,988 Bank property held for sale 1,695 FHLB and other stock 1,483 Bank owned life insurance 54,813 Other real estate owned 257 Servicing asset 1,828 Core deposit intangible 19,795 Goodwill 197,648 Deferred tax asset 3,441 Other assets 17,644 Total assets acquired $ 1,734,541 Liabilities: Deposits $ 1,321,970 Corporate debentures 9,000 Accrued interest payable 1,015 Other liabilities 13,080 Total liabilities assumed $ 1,345,065 In the acquisition, the Company acquired $1,141,672 of loans at fair value, net of $23,118, or 2.0%, estimated discount to the outstanding principal balance, representing 23.9% of the Company’s total loans at December 31, 2017. Of the total loans acquired, management identified $11,432 with credit deficiencies. All loans that were on non-accrual status, impaired loans including TDRs and some substandard loans were considered by management to be credit impaired and are accounted for pursuant to ASC Topic 310-30. The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of September 1, 2018 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 33,687 Non-accretable difference (20,763 ) Cash flows expected to be collected 12,924 Accretable yield (1,492 ) Total purchased credit-impaired loans acquired $ 11,432 The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Fair Balance Value Loans: Single family residential real estate $ 284,505 $ 280,200 Commercial real estate 567,506 557,730 Construction/development/land 181,128 178,687 Commercial loans 88,308 87,062 Consumer and other loans 26,221 26,561 Purchased credit-impaired 17,122 11,432 Total earning assets $ 1,164,790 $ 1,141,672 In its assumption of the deposit liabilities, the Company believed the deposits assumed from the acquisition have an intangible value. The Company applied ASC Topic 805, which prescribes the accounting for goodwill and other intangible assets such as core deposit intangibles, in a business combination. The Company determined the estimated fair value of the core deposit intangible asset totaled $19,795, Pro-forma information (supplemental) Pro-forma data for the twelve-month period ending December 31, 2017 listed in the table below presents pro-forma information as if the Platinum, Gateway, Sunshine, HCBF and Charter acquisitions occurred at the beginning of 2017. The pro-forma information for the twelve-month period ending December 31, 2018 assumes the Charter acquisition occurred at the beginning of 2017. Years ended December 31, 2018 2017 Net interest income $ 450,847 $ 421,556 Net income available to common shareholders $ 178,746 $ 96,633 EPS - basic $ 1.88 $ 1.04 EPS - diluted $ 1.85 $ 1.02 The disclosures regarding the results of operations for Community, Hometown, Platinum, Gateway, Sunshine, HCBF and Charter subsequent to their respective acquisition dates are omitted as this information is not practical to obtain. The Company converted Community, Hometown, Platinum, Gateway, and Sunshine’s core systems in the same quarter as their respective acquisition date. Although the Company did not convert HCBF’s core system in the first quarter of 2018 or Charter’s core system in the third quarter of 2018, the majority of the fixed costs and purchase accounting entries were booked on the Company’s core system making it impractical to determine HCBF or Charter’s results of operation on a stand-alone basis. Announced Acquisition of National Commerce Corporation On November 23, 2018, the Company entered into a definitive agreement to acquire National Commerce Corporation (“NCC”), whereby NCC will merge with and into the Company, with the Company continuing as the surviving corporation in the merger. Immediately after the merger, the Company’s subsidiary bank and NCC’s subsidiary bank, National Bank of Commerce (“NBC”), will merge with CenterState Bank as the surviving bank. Under the terms of the agreement, each outstanding share of NCC common stock will convert into the right to receive 1.65 shares of the Company’s common stock, provided that cash in lieu of any fractional shares of CenterState common stock will be paid. The transaction was unanimously approved by the boards of directors of both companies. The transaction is expected to close in the second quarter of 2019 subject to customary closing conditions, including receipt of all applicable regulatory approvals and shareholder approval of the Company and stockholder approval of NCC. The Company’s primary reasons for the transaction are to expand its core growth markets of Orlando, Tampa, Jacksonville and Atlanta, further solidify its market share in Florida, Georgia and Alabama, expand its customer base to enhance deposit fee income and leverage operating cost through economies of scale. NCC, which is headquartered in Birmingham, Alabama, operates 37 banking locations. As of December 31, 2018, NCC reported total assets of $4,210,541, total loans of $3,317,965 and total deposits of $3,432,289.

Interest Rate Swap Derivatives

Interest Rate Swap Derivatives	12 Months Ended
	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Interest Rate Swap Derivatives	(2 7 ) Interest Rate Swap Derivatives The Company enters into interest rate swaps in order to provide commercial loan clients the ability to swap from fixed to variable interest rates. Under these agreements, the Company enters into a fixed-rate loan with a client in addition to a swap agreement. This swap agreement effectively converts the client’s fixed rate loan into a variable rate. The Company then enters into a matching swap agreement with a third party dealer in order to offset its exposure on the customer swap. At years ended December 31, 2018 and 2017, the notional amount of such arrangements was $5,743,283 and $3,740,430, respectively. Due to new regulations effective in 2017, the Company pledged $28,345 and $16,991 of cash as collateral to the third party dealers at December 31, 2018 and 2017, respectively. At December 31, 2017, in addition to the cash collateral, investment securities with a fair value of $19,048 was pledged. As the interest rate swaps with the clients and third parties are not designated as hedges under ASC 815, changes in market values are reported in earnings. Summary information about the derivative instruments is as follows: 2018 2017 Notional amount $ 5,743,283 $ 3,740,430 Weighted average pay rate on interest-rate swaps 3.64 % 3.00 % Weighted average receive rate on interest rate swaps 3.64 % 3.00 % Weighted average maturity (years) 11 11 Fair value of interest rate swap derivatives (asset) 92,475 42,480 Fair value of interest rate swap derivatives (liability) 92,892 43,259

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Revenue from Contracts with Customers	(2 8 ) Revenue from Contracts with Customers On January 1, 2018, the Company adopted 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”). ASU 2014-09 implements a common revenue standard that clarifies the principles for recognizing revenue. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (i) identify the contract(s) with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The There are two reasons ASU 2014-09 did not have an impact to the Company. First, the majority of revenues are interest earned and gain on sales of loans, investment securities and other financial instruments, all of which are unaffected as they are outside the scope of ASU 2014-09. Secondly, the Company’s non-interest income revenue streams such as service charges on deposits, treasury management fees, wealth advisory fees, fixed income sales, and correspondent bank fees, are all within the scope of ASU 2014-09. However, ASC Topic 606 focuses on revenues from contracts earned over time, but all of these in-scope noninterest income revenue streams are governed by agreements that do not have an enforceable, contractual term. Given the cancellable-at-will structure, ASC Topic 606 views these contracts as agreements-at-will without a defined term, the revenues of which are immediately recognized. The revenue recognition timing is identical compared to previous revenue recognition standards. All of the Company’s revenue from contracts with customers in the scope of ASC 606 is recognized within Non-Interest Income. ASU 2014-09 requires disclosure of sufficient information to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. A description of the Company’s revenue streams accounted for under ASC 606 as well as an explanation of why they are not impacted are as follows: Revenues by Operating Segment/Line of Business Correspondent Banking Capital Markets Revenue - Fixed Income Sales The company earns commission revenues from the sale of fixed income securities to institutional investors. These revenues are earned and collected at each individual sale, and the sale is the sole performance obligation. There are no minimum orders or future performance obligations or deferred recognition requirements. Other Correspondent Banking Related Revenue The company earns revenues from a variety of services to other financial institutions including but not limited to correspondent banking, cash and clearing, safekeeping, wire transfers, international services, bond accounting, and others. Fixed income sales are discussed separately. While there is a significant variety of a la carte services, all (except fixed income sales) are either billed as incurred or are subject to monthly billing, at which point the performance obligation have been fulfilled. Even though a Correspondent agreement may provide for services over an indefinite period of time, the customer is free to end the agreement at will without penalty. This structure is viewed as an at-will agreement under ASC 606, the revenues of which are recognized immediately. Service Charges on Deposit Accounts The Company earns fees from its deposit customers for transaction-based, account maintenance, and overdraft services. Transaction-based fees, which include but are not limited to: services such as ATM use fees, stop payment charges, statement rendering, ACH fees, are recognized at the time the transaction is executed as that is the point in time the Company fulfills the customer’s request. Maintenance fees, which relate primarily to monthly maintenance, are earned over the course of a month, representing the period over which the Company satisfies the performance obligation. Overdraft fees are recognized at the point in time that the overdraft occurs. Service charges on deposits are withdrawn from the customer’s account balance. Wealth Management Related Revenue - Treasury Management The Company earns fees for Treasury Management products and services which include but are not limited to online cash management, remote deposit capture, positive pay, and lockboxes. Similar to the above service charges on deposit accounts above, these fees are also recognized at either the time the transaction or at the end of the month in the case where service obligations are provided over the course of each month. Even though a customer’s Treasury Management agreement may provide for services over an indefinite period of time, the customer is free to end the agreement at will without penalty. This structure is viewed as an at-will agreement under ASC 606, the revenues of which are recognized immediately. Wealth Management Related Revenue - Wealth Management & Advisory The Company has contracted with a third party to provide wealth management and investment brokerage services on behalf of the Company. All fees earned by the Company from Wealth Management and Advisory activities are in the form of a revenue sharing agreement. The Company acts as agent in this agreement, and as such, ASC 606 deems the third party to be the customer of the Company as opposed to those individual and entities receiving the wealth advisory services. The agreed-upon portion of revenues generated by the third party for services provided other entities and individuals are owed and remitted to the Company at the end of each month, at which time all performance obligations of the Company are fulfilled. Wealth Management Related Revenue - Trust The Company sold its Trust Department in December 2017. While there would have been ASC Topic 606 revenue recognition timing implications, the sale prior to December 31, 2017 removed these revenues from consideration. Trust revenues are displayed for prior periods only. Debit, Prepaid, ATM and Merchant Card Related Fees - Prepaid Cards The Company earns revenues from prepaid card interchange fees and maintenance fees. Interchange fees from cardholder transactions represent a portion of the underlying transaction value and are recognized daily, concurrently with the transaction processing services to the cardholder. Similar to fees from deposits accounts, maintenance fees are earned over the performance obligation period, after which all obligations have been fulfilled. Debit, Prepaid, ATM and Merchant Card Related Fees - Credit Cards The Company earns revenues from a revenue sharing agreement with a third party who provides credit card services for Company customers. Similar to the Wealth Management and Advisory revenue sharing agreement discussed above, the Company is the agent and the third party is the customer. The revenue sharing agreement calculates fees owed to the Company based on interchange and application amounts and levels. These share of fees are remitted to the Company each month, at which time the performance obligation is fulfilled. Debit, Prepaid, ATM and Merchant Card Related Fees - Debit Card Interchange Income The Company earns interchange fees from debit cardholder transactions through the MasterCard payment network. Interchange fees form cardholder transactions represent a percentage of the underlying transaction value and are recognized daily, concurrently with the transaction processing services provided to the cardholder. Gains/Losses on Sales of Repossessed Real Estate (“OREO”) The Company records a gain or loss from the sale of OREO when control of the property transfers to the buyer, which generally occurs at the time of an executed deed. There are no ASC 606 implications unless the Company finances the sale of OREO. There are no instances of the Company financing the sale of one of its OREO properties as of September 30, 2018. Contract Balances The Contract Balances disclosure requirement is not relevant, as no revenues are earned over time that would require the monitoring of contract balances. The Performance Obligations disclosure requirements call for a description of when performance obligations are satisfied, significant payment terms, nature of goods or services promised, and obligations for returns, refunds, and warranties.

Capital Raise

Capital Raise	12 Months Ended
	Dec. 31, 2018
Capital Raise [Abstract]
Capital Raise	(2 9 ) Capital Raise On January 13, 2017, the Company raised approximately $63,791 through a public offering by issuing 2,695,000 shares of common stock, including 245,000 shares pursuant to the exercise of the underwriters’ over-allotment option. Net proceeds of the offering, after all expenses, were approximately $63,262.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Nature of Operations and Principles of Consolidation	(a) Nature of operations and principles of consolidation The Consolidated Financial Statements of CenterState Bank Corporation (the “Company”) include the accounts of the Company, and its wholly owned subsidiaries CenterState Bank, N.A., R4ALL, Inc. and CSFL Insurance Corp. All significant intercompany accounts and transactions have been eliminated in consolidation. At December 31, 2018, the Company, through its subsidiary bank, operated as a community bank headquartered in the state of Florida, providing traditional retail, commercial, mortgage, wealth management and SBA services throughout its Florida, Georgia and Alabama branch network and customer relationships in neighboring states. The Company’s primary deposit products are checking, savings and term certificate accounts, and its primary lending products include commercial real estate loans, residential real estate loans, commercial loans and consumer loans. Substantially all loans are secured by commercial real estate, residential real estate, business assets or consumer assets. There are no significant concentrations of loans to any one industry or customer. However, the customers’ ability to repay their loans is dependent on the real estate and general economic conditions in the area. The Company also provides correspondent banking and capital markets services to over 600 community banks nationwide. R4ALL, Inc. is a non bank subsidiary incorporated during the third quarter of 2009. The primary purpose of this subsidiary is to purchase, hold, and dispose of troubled assets acquired from the Company’s subsidiary bank. CSFL Insurance Corp. is a non bank subsidiary incorporated during the fourth quarter of 2015. The primary purpose of this subsidiary is to function as a captive insurance subsidiary pursuant to Section 831(b) of the U.S. Tax Code. The following is a description of the basis of presentation and the significant accounting and reporting policies, which the Company follows in preparing and presenting its Consolidated Financial Statements.
Use of Estimates	(b) Use of estimates To prepare financial statements in conformity with U.S. generally accepted accounting principles, management makes estimates and assumptions based on available information. These estimates and assumptions affect the amounts reported in the financial statements and the disclosures provided. Significant items subject to estimates and assumptions include allowance for loan losses, fair values of financial instruments, useful life of intangibles and valuation of goodwill, fair value estimates of stock-based compensation, fair value estimates of OREO, and deferred tax assets. Actual results could differ from these estimates.
Cash Flow Reporting	(c) Cash flow reporting For purposes of the statement of cash flows, the Company considers cash and due from banks, federal funds sold, money market and non-interest bearing deposits in other banks with a purchased maturity of three months or less to be cash equivalents. Net cash flows are reported for customer loan and deposit transactions, interest bearing deposits in other financial institutions, federal funds purchased, repurchase agreements, proceeds from capital offering and other borrowed funds.
Interest Bearing Deposits in Other Financial Institutions	(d) Interest bearing deposits in other financial institutions Interest bearing deposits in other financial institutions mature within one year and are carried at cost and are included in Cash and Due From Banks in the Consolidated Balance Sheets.
Trading Securities	(e) The Company engages in trading activities for its own account. Securities that are held principally for resale in the near term are recorded at fair value with changes in fair value included in earnings. Interest is included in net interest income.
Investment Debt Securities	(f) Investment Debt Securities Debt securities are classified as held to maturity and carried at amortized cost when management has the positive intent and ability to hold them to maturity. Debt securities not classified as held to maturity or trading are classified as available for sale. Debt s ecurities available for sale are carried at fair value, with unrealized holding gains and losses reported in other comprehensive income, net of tax. Interest income includes amortization of purchase premium or discount. Premiums on securities are amortized to the earliest call date. Discounts on securities are amortized on the level-yield method without anticipating prepayments, except for mortgage backed securities where prepayments are anticipated. Gains and losses on sales are recorded on the trade date and determined using the specific identification method. Securities are evaluated for other-than-temporary impairment (“OTTI”) on at least an annual basis, and more frequently when economic or market conditions warrant such an evaluation. For securities in an unrealized loss position, management considers the extent and duration of the unrealized loss, and the financial condition and near-term prospects of the issuer. Management also assesses whether it intends to sell, or it is more likely than not that it will be required to sell, a security in an unrealized loss position before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the entire difference between amortized cost and fair value is recognized as impairment through earnings. For debt securities that do not meet the aforementioned criteria, the amount of impairment is split into two components as follows: 1) OTTI related to credit loss, which must be recognized in the income statement; and 2) other-than-temporary impairment related to other factors, which is recognized in other comprehensive income. The credit loss is defined as the difference between the present value of the cash flows expected to be collected and the amortized cost basis.
Bond Commissions Revenue Recognition	(g) Bond commissions revenue recognition Bond sales transactions and related revenue and expenses are recorded on a settlement date basis. The effect on the financial statements of using the settlement date basis rather than the trade date basis is not material.
Loans Held for Sale	(h) Loans held for sale Effective January 1, 2018, mortgage loans originated and intended for sale in the secondary market are carried at fair value with changes in fair value recognized in current period earning. For periods prior to December 31, 2018, mortgage loans held for sale were carried at the lower of aggregate cost or fair value, as determined by outstanding commitments from investors. Net unrealized losses, if any, are recorded as a valuation allowance and charged to earnings. Mortgage loans held for sale are generally sold with servicing rights released. Gains and losses on sales of mortgage loans are based on the difference between the selling price and the carrying value of the related loan sold.
Loans	(i) Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at their outstanding unpaid principal balance net of purchase premiums and discounts, deferred loan fees and costs, and an allowance for loan losses. Interest income is accrued on the unpaid principal balance. The recorded investment in a loan excludes accrued interest receivable, deferred fees, and deferred costs because they are not considered material. A loan is considered a troubled debt restructured loan based on individual facts and circumstances. A modification may include either an increase or reduction in interest rate or deferral of principal payments or both. Loans for which the terms have been modified resulting in a concession, and for which the borrower is experiencing financial difficulties, are considered troubled debt restructurings. The Company classifies troubled debt restructured loans as impaired and evaluates the need for an allowance for loan losses on a loan-by-loan basis. An allowance for loan losses is based on either the present value of estimated future cash flows or the estimated fair value of the underlying collateral. Loans retain their accruing or non-accruing status at the time of modification. Loan origination fees and the incremental direct cost of loan origination, are deferred and recognized in interest income without anticipating prepayments over the contractual life of the loans. If the loan is prepaid, the remaining unamortized fees and costs are charged or credited to interest income. Amortization ceases for non-accrual loans. A loan is moved to non-accrual status in accordance with the Company’s policy typically after 90 days of non-payment, or less than 90 days of non-payment if management determines that the full timely collection of principal and interest becomes doubtful. Past due status is based on the contractual terms of the loan. In all cases, loans are placed on non-accrual or charged-off at an earlier date if collection of principal or interest is considered doubtful. Non-accrual loans and loans past due 90 days still on accrual include both smaller balance homogeneous loans that are collectively evaluated for impairment and individually classified impaired loans. Single family home loans, consumer loans and smaller commercial, land, development and construction loans (less than $ 500 ) are monitored by payment history, and as such, past due payments is generally the triggering mechanism to determine non - accrual status. Larger (greater than $ 500 ) commercial, land, development and construction loans are monitored on a loan level basis, and therefore in these cases it is more likely that a loan may be placed on non - accrual status before it becomes 90 days past due. All interest accrued but not received for loans placed on non-accrual is reversed against interest income. Interest received on such loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured. Non real estate consumer loans are typically charged off no later than 120 days past due. The Company, considering current information and events regarding the borrower’s ability to repay their obligations, considers a loan to be impaired when it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement. When a loan is considered to be impaired, the amount of the impairment is measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, the secondary market value of the loan, or the fair value of the collateral for collateral dependent loans. Interest income on impaired loans is recognized in accordance with the Company’s non-accrual policy. Impaired loans are written down to the extent that principal is judged to be uncollectible and, in the case of impaired collateral dependent loans where repayment is expected to be provided solely by the underlying collateral and there is no other available and reliable sources of repayment, are written down to the lower of cost or collateral value less estimated selling costs. Impairment losses are included in the allowance for loan losses. Large groups of smaller balance homogeneous loans, such as consumer and residential real estate loans, are collectively evaluated for impairment, and accordingly, they are not separately identified for impairment disclosures.
Purchased Credit-Impaired Loans	(j) Purchased credit-impaired loans As a part of business acquisitions, the Company acquires loans, some of which have shown evidence of credit deterioration since origination. These purchased credit-impaired (“PCI”) loans were determined to be credit impaired based on specific risk characteristics of the loan, including, but not limited to loans on non-accrual status, loans with insufficient cash flow, past due loans, high loan-to-value ratios, loans in process of foreclosure, or any TDR with loss potential. The Company, as a purchaser, is permitted to aggregate credit impaired loans acquired in the same fiscal quarter into one or more pools, provided that the loans have common risk characteristics. A pool is then accounted for as a single asset with a single composite interest rate and an aggregate expectation of cash flows. For the loan portfolios acquired, the Company aggregated the commercial, consumer, and residential loans into pools of loans with common risk characteristics for each institution acquired. These acquired loans were recorded at the acquisition date fair value, and after acquisition, losses are recognized through the allowance for loan losses. The Company estimates the amount and timing of expected cash flows for each acquired loan pool and the expected cash flows in excess of the amount paid is recorded as interest income over the remaining life of the loan pools. As frequently as quarter or as long as annually, the Company updates the amount of loan principal and interest cash flows expected to be collected, incorporating assumptions regarding default rates, loss severities, the amounts and timing of prepayments and other factors that are reflective of current market conditions. Probable decreases in expected loan principal cash flows trigger the recognition of impairment, which is measured as the present value of the expected principal loss plus any related foregone interest cash flows discounted at the pool’s effective interest rate. Impairments that occur after the acquisition date are recognized through provision for loan losses. Probable and significant increases in expected principal cash flows would first reverse any previously recorded allowance for loan losses; any remaining increases are recognized prospectively as interest income over the life of the pool. The impacts of (i) prepayments, (ii) changes in variable interest rates, and (iii) any other changes in the timing of expected cash flows are recognized prospectively as adjustments to interest income over the life of the pool. Disposals of loans, which may include sales of loans, receipt of payments in full by the borrower, or foreclosure, result in removal of the loan from the purchased credit impaired portfolio.
Concentration of Credit Risk	(k) Concentration of credit risk Most of the Company’s business activity is with customers located within Southeastern United States largely in Florida, also in Alabama and Georgia. Therefore, the Company’s exposure to credit risk is significantly affected by changes in the economy and the real estate market within Southeast, primarily in Florida.
Allowance for Loan Losses	(l) Allowance for loan losses The allowance for loan losses is a valuation allowance for probable incurred credit losses. Loan losses are charged against the allowance when management believes the uncollectibility of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance. Management estimates the allowance balance required using past loan loss experience, the nature and volume of the portfolio, information about specific borrower situations and estimated collateral values, economic conditions, and other factors. Allocations of the allowance may be made for specific loans, but the entire allowance is available for any loan that, in management’s judgment, should be charged-off. The allowance consists of specific and general components. The specific component relates to loans that are individually classified as impaired. The general component covers loans that are not individually classified as impaired and is based on historical loss experience adjusted for current factors. A loan is impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement. Loans, for which the terms have been modified resulting in a concession, and for which the borrower is experiencing financial difficulties, are considered troubled debt restructurings and classified as impaired. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. If a loan is impaired, a portion of the allowance is allocated so that the loan is reported, net, at the present value of estimated future cash flows using the loan’s existing rate or at the fair value of collateral if repayment is expected solely from the collateral. Commercial, commercial real estate, land, acquisition and development, and construction loans over $500 are individually evaluated for impairment. Large groups of smaller balance homogeneous loans, such as consumer and residential real estate loans, are collectively evaluated for impairment, and accordingly, they are not separately identified for impairment disclosures. Troubled debt restructurings are separately identified for impairment disclosures and are measured at the present value of estimated future cash flows using the loan’s effective rate. If a troubled debt restructuring is considered to be a collateral dependent loan, the loan is reported, net, at the fair value of the collateral. For troubled debt restructurings that subsequently default, the Company determines the amount of reserve in accordance with the accounting policy for the allowance for loan losses. The general component covers non-impaired loans and is based on historical loss experience adjusted for current factors. The historical loss experience is determined by portfolio segment and is based on the actual loss history experienced by the Company over the most recent two years. The portfolio segments identified by the Company are residential loans, commercial real estate loans, construction and land development loans, commercial and industrial and consumer and other. This actual loss experience is supplemented with other economic factors based on the risks present for each portfolio segment. These economic factors include consideration of the following: levels of and trends in delinquencies and impaired loans; volume and severity of adversely classified or graded loans; levels of and trends in charge-offs and recoveries; trends in volume and terms of loans; effects of any changes in risk selection and underwriting standards; other changes in lending policies, procedures, and practices; experience, ability, and depth of lending management and other relevant staff; national and local economic trends and conditions; industry conditions; and effects of changes in credit concentrations. The Company segregates and evaluates its loan portfolio through the five portfolio segments: residential real estate, commercial real estate, land/ land development/construction, commercial and consumer/other. Residential real estate loans are a mixture of fixed rate and adjustable rate residential mortgage loans, including first mortgages, second mortgages or home equity lines of credit. As a policy, the Company holds adjustable rate loans and sells a portion of its fixed rate loan originations into the secondary market. Changes in interest rates or market conditions may impact a borrower’s ability to meet contractual principal and interest payments. Residential real estate loans are secured by real property. Commercial real estate loans include loans secured by office buildings, warehouses, retail stores and other property located in or near our markets. These loans are originated based on the borrower’s ability to service the debt and secondarily based on the fair value of the underlying collateral. Land/land development/construction loans include residential and commercial real estate loans and include a mixture of owner occupied and non-owner occupied. The majority of the loans in this category are land related, either undeveloped land, land held for development, residential building lots and commercial building lots. Generally the terms are three to five years, with a potential for renewal at maturity. Commercial loans consist of small-to medium-sized businesses including professional associations, medical services, retail trade, transportation, wholesale trade, manufacturing and tourism. Commercial loans are derived from our market areas and underwritten based on the borrower’s ability to service debt from the business’s underlying cash flows. As a general practice, we obtain collateral such as inventory, accounts receivable, equipment or other assets although such loans may be uncollateralized but guaranteed. Consumer and other loans include automobiles, boats, mobile homes without land, or uncollateralized but personally guaranteed loans. These loans are originated based primarily on credit scores, debt-to-income ratios and loan-to-value ratios. The Company evaluates the loans acquired from the Gulfstream, First Southern, Community Bank, First National, Platinum and Gateway acquisitions that were not PCI loans as individual loan portfolio segments. The Company considered the levels of and trends in non-performing loans, past-due loans, adverse loan grade classification changes, historical loss rates, environmental factors and impaired loans in arriving at its estimate. The general loan loss allowance recorded for these performing loans acquired from Gulfstream is allocated between the five portfolio segments described above in Note 5.
Transfer of Financial Assets	(m) Transfer of financial assets Transfers of financial assets are accounted for as sales, when control over the assets has been relinquished. Control over transferred assets is deemed to be surrendered when the assets have been isolated from the Company, the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.
Other Repossessed Real Estate Owned	(n) Other repossessed real estate owned Assets acquired through or instead of loan foreclosure are initially recorded at fair value less costs to sell when acquired, establishing a new cost basis. These assets are subsequently accounted for at lower of cost or fair value less estimated costs to sell. If fair value declines subsequent to foreclosure, a valuation allowance is recorded through expense. Operating costs after acquisition are expensed. Repossessed real estate is included in other repossessed real estate owned and other repossessed assets other than real estate is included in Prepaid Expenses and Other Assets in the Consolidated Balance Sheets.
Premises and Equipment	(o) Premises and equipment Land is carried at cost. Premises and equipment are stated at cost less accumulated depreciation. Depreciation is provided on a straight-line basis over the estimated useful lives of the related assets. Buildings are depreciated over a 39 year period, and furniture, fixtures and equipment are depreciated over their related useful life (3 to 15 years). Leasehold improvements are depreciated over the shorter of their useful lives or the term of the lease. Major renewals and betterments of property are capitalized; maintenance, repairs, and minor renewals and betterments are expensed in the period incurred. Upon retirement or other disposition of the asset, the asset cost and related accumulated depreciation are removed from the accounts, and gains or losses are included in income.
Software Costs	(p) Software costs Costs of software developed for internal use, such as those related to software licenses, programming, testing, configuration, direct materials and integration, are capitalized and included in premises and equipment. Included in the capitalized costs are those costs related to both our personnel and third party consultants involved in the software development and installation. Once placed in service, the capitalized asset is amortized on a straight-line basis over its estimated useful life, generally three to five years. Capitalized costs of software developed for internal use are reviewed periodically for impairment.
Federal Home Loan Bank (FHLB), Federal Reserve Bank (FRB) and Other Stock	(q) Federal Home Loan Bank (FHLB), Federal Reserve Bank (FRB) and other stock The Company’s subsidiary bank is a member of the FHLB and FRB system. Members are required to own a certain amount of stock based on the level of borrowings and other factors, and may invest in additional amounts. FHLB, FRB and other stock is carried at cost, classified as a restricted security, and periodically evaluated for impairment based on ultimate recovery of par value. Both cash and stock dividends are reported as income.
Bank Owned Life Insurance (BOLI)	(r) Bank owned life insurance (BOLI) The Company, through its subsidiary bank, has purchased life insurance policies on certain key executives or acquired through various bank acquisitions. Bank owned life insurance is recorded at the amount that can be realized under the insurance contract at the balance sheet date, which is the cash surrender value adjusted for other charges or other amounts due that are probable at settlement.
Goodwill and Other Intangible Assets	(s) Goodwill and other intangible assets Goodwill resulting from business combinations prior to January 1, 2009 represents the excess of the purchase price over the fair value of the net assets of businesses acquired. Goodwill resulting from business combinations after January 1, 2009, is generally determined as the excess of the fair value of the consideration transferred, plus the fair value of any noncontrolling interests in the acquiree, over the fair value of the net assets acquired and liabilities assumed as of the acquisition date. Goodwill and intangible assets acquired in a purchase business combination and determined to have an indefinite useful life are not amortized, but tested for impairment at least annually. The Company has selected November 30 as the date to perform the annual impairment test. Intangible assets with definite useful lives are amortized over their estimated useful lives to their estimated residual values. Goodwill is the only intangible asset with an indefinite life on the Company’s balance sheet. The core deposit intangibles are intangible assets arising from either whole bank acquisitions or branch acquisitions. They are initially measured at fair value and then amortized over a ten-year period on an accelerated basis using the projected decay rates of the underlying core deposits. As a part of normal business operations, the Company originates residential mortgage loans that have been pre-approved by secondary investors. The terms of the loans are set by the secondary investors, and the purchase price that the investor will pay for the loan is agreed to prior to the commitment of the loan by the Company. Generally within three weeks after funding, the loans are transferred to the investor in accordance with the agreed-upon terms. The Company records gains from the sale of these loans on the settlement date of the sale equal to the difference between the proceeds received and the carrying amount of the loan. The gain generally represents the portion of the proceeds attributed to servicing release premiums received from the investors and the realization of origination fees received from borrowers which were deferred as part of the carrying amount of the loan. Between the initial funding of the loans by the Company and the subsequent reimbursement by the investors, the Company carries the loans on its balance sheet at the lower of cost or market. The fair value of the underlying commitment is not material to the Consolidated Financial Statements. The standard structure of mortgage loan sales provides for the Company to retain a portion of the cash flow from the interest payments received on the loan. Fees for servicing loans for investors are based on the outstanding principal balance of the loans serviced and are recognized as income when earned. This cash flow is commonly known as a servicing spread. The servicing spread is recognized as a servicing asset to the extent the spread exceeds adequate compensation for the servicing function and recorded as a component of Other Intangible Assets in the Consolidated Balance Sheets. The fair value of the servicing asset is measured on a recurring basis at the present value of future cash flows using market-based discount assumptions. The future cash flows for each asset are based on their unique characteristics and market-based assumptions for prepayment speeds, default and voluntary prepayments. Adjustments to fair value are recorded as a component of Mortgage Banking Revenue. The value of our servicing portfolio is periodically independently evaluated.
FDIC Indemnification Asset	(t) FDIC Indemnification Asset The FDIC Indemnification Asset represented the estimated amounts due from the FDIC pursuant to the Loss Share Agreements related to the acquisitions of the three failed banks acquired in 2010, two in 2012 and assumed two additional pursuant to the Company’s 2014 acquisition of First Southern. At acquisition, the FDIC Indemnification Asset represented the discounted value of the FDIC’s reimbursed portion of the estimated losses the Company expects to realize on the loans and other real estate (“Covered Assets”) acquired as a result of the acquisitions. The range of discount rates used on the FDIC Indemnification Asset was 1.21% to 4.53%. As losses were realized on Covered Assets, the portion that the FDIC paid the Company in cash for principal and up to 90 days of interest reduced the FDIC Indemnification Asset. On a quarterly basis, the Company evaluated the FDIC Indemnification Asset to determine if the estimated losses on Covered Assets supported the amount recorded as the FDIC Indemnification Asset. Income accretion was recognized during the loss share period. If the expectation of future losses declined, the income accretion was reduced prospectively over the lesser of the term of the loss share agreement and the estimated remaining life of the Covered Asset. On February 3, 2016, the FDIC bought out the remaining FDIC loss share agreements. As such, the FDIC indemnification asset was written-off effectively accelerating all future FDIC indemnification asset amortization expense as well as ending any future FDIC indemnification income.
Loan Commitments and Related Financial Instruments	(u) Loan commitments and related financial instruments Financial instruments include off-balance sheet credit instruments, such as commitments to make loans and commercial letters of credit, issued to meet customer financing needs. The face amount for these items represents the exposure to loss, before considering customer collateral or ability to repay. Such financial instruments are recorded when they are funded.
Stock-Based Compensation	(v) Stock-based compensation Compensation cost is recognized for stock options and restricted stock awards issued to employees, based on the fair value of these awards at the date of grant. A Black-Scholes model is utilized to estimate the fair value of stock options, while the market price of the Company’s common stock at the date of grant is used for restricted stock awards. During 2014 the Company initiated a Long-Term Incentive Plan which included Performance Share Units (“PSUs”). The Monte-Carlo Simulation model was used to estimate fair value of the PSUs at the grant date. Compensation cost is recognized over the required service period, generally defined as the vesting period.
Income Taxes	(w) Income taxes Income tax expense is the total of the current year income tax due or refundable and the change in deferred tax assets and liabilities. Deferred tax assets and liabilities are the expected future tax amounts for the temporary differences between carrying amounts and tax bases of assets and liabilities, computed using enacted tax rates. A valuation allowance, if needed, reduces deferred tax assets to the amount expected to be realized. A tax position is recognized as a benefit only if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit that is greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded. The Company recognizes interest and/or penalties related to income tax matters in other expenses. On December 22, 2017, the U.S. federal government enacted a tax bill, H.R1 (“Tax Act”) which reduced the federal corporate tax rates effective for fiscal year 2018. As a result of this new tax bill, the Company evaluated its deferred tax assets and deferred tax liabilities to account for the future impact of lower corporate tax rates on its deferred tax assets. The reduction in the federal corporate tax rate resulted in a one-time charge to the Company’s 2017 earnings and reduction to its net deferred tax assets. See Note 14 for more details regarding Income Taxes.
Retirement Plans	(x) Retirement plans Employee 401(k) plan expense is the amount of matching contributions. Deferred compensation and supplemental retirement plan expense allocates the benefits over years of service.
Marketing and Advertising Costs	(y) Marketing and advertising costs Marketing and advertising costs are expensed as incurred.
Earnings Per Common Share	(z) Basic earnings per common share is net income divided by the weighted average number of common shares outstanding during the period. All outstanding unvested share-based payment awards that contain rights to nonforfeitable dividends are considered participating securities for this calculation. Diluted earnings per common share includes the dilutive effect of additional potential common shares issuable under stock options and unvested restricted stock awards where shares are not issued until vested. Earnings and dividends per share are restated for all stock splits and stock dividends through the date of issuance of the financial statements.
Comprehensive Income	(aa) Comprehensive income Comprehensive income consists of net income and other comprehensive income. Other comprehensive income includes unrealized gains and losses on securities available for sale, which are also recognized as separate components of shareholders’ equity.
Loss Contingencies	(ab) Loss contingencies Loss contingencies, including claims and legal actions arising in the ordinary course of business, are recorded as liabilities when the likelihood of loss is probable and an amount or range of loss can be reasonably estimated. Management does not believe there now are such matters that will have a material effect on the financial statements.
Restrictions on Cash	(ac) Restrictions on cash Cash on hand or on deposit with the Federal Reserve Bank is generally required to meet regulatory reserve and clearing requirements. Cash is required to be pledged as collateral to the third party dealers for the interest rate swap derivatives.
Dividend Restriction	(ad) Dividend restriction Banking regulations require maintaining certain capital levels and may limit the dividends paid by the bank to the holding company or by the holding company to shareholders.
Fair Value of Financial Instruments	(ae) Fair value of financial instruments Fair values of financial instruments are estimated using relevant market information and other assumptions, as more fully disclosed in a separate note. Fair value estimates involve uncertainties and matters of significant judgment regarding interest rates, credit risk, prepayments, and other factors, especially in the absence of broad markets for particular items. Changes in assumptions or in market conditions could significantly affect the estimates.
Segment Reporting	(af) Segment reporting The Company’s correspondent banking and capital markets division represents a distinct reportable segment which differs from the Company’s primary business of commercial and retail banking in Florida, Georgia and Alabama. Accordingly, a reconciliation of reportable segment revenues, expenses and profit to the Company’s consolidated total has been presented in Note 25.
Derivatives	(ag) Derivatives The Company enters into interest rate swaps in order to provide commercial loan clients the ability to swap from fixed to variable interest rates. Under these agreements, the Company enters into a fixed-rate loan with a client in addition to a swap agreement. This swap agreement effectively converts the client’s fixed rate loan into a variable rate. The Company then enters into a matching swap agreement with a third party dealer in order to offset its exposure on the customer swap. The Company does not use derivatives for trading purposes. The derivative transactions are considered instruments with no hedging designation, otherwise known as stand-alone derivatives. Changes in the fair value of the derivatives are reported currently in earnings.
Reclassifications	(ah) Reclassifications Some items in the prior year financial statements were reclassified to conform to the current presentation. Reclassifications had no effect on prior years’ net income or shareholders’ equity.
Effect of New Pronouncements	(ai ) Effect of new pronouncements In January 2016, the FASB issued ASU No. 2016-01, "Recognition and Measurement of Financial Assets and Financial Liabilities." This ASU addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments by making targeted improvements to GAAP as follows: (1) require equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. However, an entity may choose to measure equity investments that do not have readily determinable fair values at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer; (2) simplify the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment. When a qualitative assessment indicates that impairment exists, an entity is required to measure the investment at fair value; ( 3 ) eliminate the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; ( 4 ) require public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; ( ( 5 ) require separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or the accompanying Notes to the Financial Statements ; and ( 6 ) clarify that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. ASU No. 2016-01 is effective for interim and annual reporting periods beginning after December 15, 2017. Starting with the first quarter of 2018, the Company began using an exit price notion when measuring the fair value of its loan portfolio, excluding loans held for sale, for disclosure purposes. The new guidance did not impact the Company's Consolidated Financial Statements. In February 2016, the FASB issued ASU No. 2016-02, "Leases." Under this guidance, lessees will be required to recognize the following for all leases (with the exception of short-term leases): 1) a lease liability, which is the present value of a lessee's obligation to make lease payments, and 2) a right-of-use asset, which is an asset that represents the lessee's right to use, or control the use of, a specified asset for the lease term. Lessor accounting under the new guidance remains largely unchanged as it is substantially equivalent to existing guidance for sales-type leases, direct financing leases, and operating leases. Leveraged leases have been eliminated, although lessors can continue to account for existing leveraged leases using the current accounting guidance. Other limited changes were made to align lessor accounting with the lessee accounting model and the new revenue recognition standard. All entities will classify leases to determine how to recognize lease-related revenue and expense. Quantitative and qualitative disclosures will be required by lessees and lessors to meet the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The intention is to require enough information to supplement the amounts recorded in the financial statements so that users can understand more about the nature of an entity’s leasing activities. ASU No. 2016-02 is effective for interim and annual reporting periods beginning after December 15, 2018; early adoption is permitted. All entities are required to use a modified retrospective approach for leases. Management is electing the effective date method of the modified retrospective transition approach. Under the effective date method, all lease accounting transitions to ASC 842 as of January 1, 2019 through a one-time recognition of previously off-balance sheet leases as well as a one-time offset to retained earnings for measurement differences. Under the effective date transition approach, all comparative periods presented prior to January 1, 2019 will remain in accordance with legacy lease accounting of ASC 840. The Company leases certain properties and equipment under operating leases that will result in the recognition of right-of-use lease assets of approximately $21 million and lease liabilities of approximately $24 million In June 2016, the FASB issued ASU No. 2016-13, “Measurement of Credit Losses on Financial Instruments.” This ASU significantly changes how entities will measure credit losses for most financial assets and certain other instruments that aren’t measured at fair value through net income. In issuing the standard, the FASB is responding to criticism that today’s guidance delays recognition of credit losses. The standard will replace today’s “incurred loss” approach with an “expected loss” model. The new model, referred to as the current expected credit loss (“CECL”) model, will apply to: (1) financial assets subject to credit losses and measured at amortized cost, and (2) certain off-balance sheet credit exposures. This includes, but is not limited to, loans, leases, held-to-maturity securities, loan commitments, and financial guarantees. The CECL model does not apply to available-for-sale (“AFS”) debt securities. For AFS debt securities with unrealized losses, entities will measure credit losses in a manner similar to what they do today, except that the losses will be recognized as allowances rather than reductions in the amortized cost of the securities. As a result, entities will recognize improvements to estimated credit losses immediately in earnings rather than as interest income over time, as they do today. The ASU also simplifies the accounting model for purchased credit-impaired debt securities and loans. ASU 2016-13 also expands the disclosure requirements regarding an entity’s assumptions, models, and methods for estimating the allowance for loan and lease losses. In addition, entities will need to disclose the amortized cost balance for each class of financial asset by credit quality indicator, disaggregated by the year of origination. ASU No. 2016-13 is effective for interim and annual reporting periods beginning after December 15, 2019; early adoption is permitted for interim and annual reporting periods beginning after December 15, 2018. Entities will apply the standard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective (i.e., modified retrospective approach). The Company formed a CECL committee to assist with the implementation process . It has selected a third-party vendor to assist with the allowance for loan loss methodology as well as advisory services related to the implementation of the amendments of ASU 2016-13. The Company continues to work with the third-party vendor to develop the CECL model and evaluate the impact to the Company’s Consolidated Financial Statements. The standard will add new disclosures related to factors that influenced management’s estimate, including current expected credit losses, the changes in those factors, and reasons for the changes as well as the method applied to revert to historical credit loss experience, and the Company expects to recognize a one-time cumulative effect adjustment to the allowance for loan losses as of the beginning of the first reporting period in which the new standard is effective, but has not yet determined the magnitude of any such one-time adjustment or the overall impact on the Company’s Financial Statements . In January 2017, the FASB issued ASU No. 2017-04, “Simplifying the Test for Goodwill Impairment,” to simplify how an entity is required to test goodwill for impairment by eliminating Step 2 from the goodwill impairment test. Step 2 measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. In In May 2017, the FASB issued ASU 2017-09, “Scope of Modification Accounting,” to provide clarity and reduce both (1) diversity in practice and (2) cost and complexity when applying the guidance in Topic 718, “Compensation—Stock Compensation,” to a change to the terms or conditions of a share-based payment award. The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. An entity should account for the effects of a modification unless all the following are met: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified. If the modification does not affect any of the inputs to the valuation technique that the entity uses to value the award, the entity is not required to estimate the value immediately before and after the modification; (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; (3) the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The current disclosure requirements in Topic 718 apply regardless of whether an entity is required to apply modification accounting under the amendments in this update . In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities.” The amendments in this update more closely align the results of cash flow and fair value hedge accounting with risk management activities through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results in the financial statements. The amendments address specific limitations in current GAAP by expanding hedge accounting for both nonfinancial and financial risk components and by refining the measurement of hedge results to better reflect an entity’s hedging strategies. Thus, the amendments will enable an entity to report more faithfully the economic results of hedging activities for certain fair value and cash flow hedges and will avoid mismatches in earnings by allowing for greater precision when measuring changes in fair value of the hedged item for certain fair value hedges. Additionally, by aligning the timing of recognition of hedge results with the earnings effect of the hedged item for cash flow and net investment hedges, and by including the earnings effect of the hedging instrument in the same income statement line item in which the earnings effect of the hedged item is presented, the results of an entity’s hedging program and the cost of executing that program will be more visible to users of financial statements. Overall, those amendments are an improvement because an entity’s financial statements will reflect more accurately and comprehensively the intent and outcome of its hedging strategies. The tabular disclosure related to effects on the income statement of fair value and cash flow hedges and the disclosure of cumulative basis adjustments for fair value hedges provide users with a more complete picture of the effect of hedge accounting on an entity’s income statement and balance sheet. When considered together, the amendments to presentation and disclosures are an improvement because they will provide users with more decision-useful information about the effect of an entity’s risk management activities on the financial statements. Additionally, the amendments in this Update should ease the operational burden of applying hedge accounting by allowing more time to prepare hedge documentation and, allowing effectiveness assessments to be performed on a qualitative basis after hedge inception. For public business entities, the amendments in this update become effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. All transition requirements and elections should be applied to hedging relationships existing (that is, hedging relationships in which the hedging instrument has not expired, been sold, terminated, or exercised or the entity has not removed the designation of the hedging relationship) on the date of adoption. The effect of adoption should be reflected as of the beginning of the fiscal year of adoption (that is, the initial application date). For cash flow and net investment hedges existing at the date of adoption, an entity should apply a cumulative-effect adjustment related to eliminating the separate measurement of ineffectiveness to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings as of the beginning of the fiscal year that an entity adopts the amendments in this Update. The amended presentation and disclosure guidance is required only prospectively. The Company evaluated the impact of adopting the new guidance on the Consolidated Financial Statements, but it does not have a material impact. In February 2018, the FASB issued ASU 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. On December 22, 2017, the U.S. federal government enacted the Tax Act. Stakeholders in the banking and insurance industries expressed concern about the guidance in current generally accepted accounting principles (GAAP) that requires deferred tax liabilities and assets to be adjusted for the effect of a change in tax laws or rates with the effect included in income from continuing operations in the reporting period that includes the enactment date. That guidance is applicable even in situations in which the related income tax effects of items in accumulated other comprehensive income were originally recognized in other comprehensive income (rather than in income from continuing operations). Those stakeholders asserted that because the adjustment of deferred taxes due to the reduction of the historical corporate income tax rate to the newly enacted corporate income tax rate is required to be included in income from continuing operations, the tax effects of items within accumulated other comprehensive income (referred to as stranded tax effects) do not reflect the appropriate tax rate. The amendments in this update affect any entity that is required to apply the provisions of Topic 220, Income Statement—Reporting Comprehensive Income, and has items of other comprehensive income for which the related tax effects are presented in other comprehensive income as required by GAAP. The amendments in this update allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Act. Consequently, the amendments eliminate the stranded tax effects resulting from the Tax Act and will improve the usefulness of information reported to financial statement users. The amendments only relate to the reclassification of the income tax effects of the Tax Act; the underlying guidance that requires that the effect of a change in tax laws or rates be included in income from continuing operations is not affected. The amendments in this update also require certain disclosures about stranded tax effects. The amendments in this update are effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. The amendments in this update should be applied either in the period of adoption or retrospectively to each period (or periods) in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Act is recognized. The Company early adopted this update which resulted in a reclassification of $1,241 In June 2018, the FASB issued ASU No. 2018-07, “Compensation – Stock Compensation (Topic 718) - Improvements to Nonemployee Share-Based Payment Accounting,” to include share based payment transactions for acquiring goods and services from nonemployees. An entity should apply the requirements of Topic 718 to nonemployee awards except for specific guidance on inputs to an option pricing model and the attribution of cost (that is, the period of time over which share-based payment awards vest and the pattern of cost recognition over that period). The amendments specify that Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in a grantor’s own operations by issuing share-based payment awards. The amendments also clarify that Topic 718 does not apply to share-based payments used to effectively provide (1) financing to the issuer or (2) awards granted in conjunction with selling goods or services to customers as part of a contract accounted for under Topic 606, Revenue from Contracts with Customers. The amendments in this update become effective for annual periods and interim periods within those annual periods beginning after December 15, 2018 but no earlier than an entity’s adoption date of Topic 606. The Company evaluated the impact of adopting the new guidance on the Consolidated Financial Statements, but it does not have a material impact. In August 2018, the FASB issued ASU No. 2018-13, “Fair Value Measurement (Topic 820) - Changes to the Disclosure Requirements for Fair Value Measurement,” to modify the disclosure requirements on fair value measurements in Topic 820 based on the concepts in the Concepts Statement, including the consideration of costs and benefits. The following disclosure requirements were removed from Topic 820: (1) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy; (2) the policy for timing of transfers between levels; (3) the valuation processes for Level 3 fair value measurements; and (4) for nonpublic entities, the changes in unrealized gains and losses for the period included in earnings for recurring Level 3 fair value measurements held at the end of the reporting period. The following disclosure requirements were modified in Topic 820: (1) in lieu of a rollforward for Level 3 fair value measurements, a nonpublic entity is required to disclose transfers into and out of Level 3 of the fair value hierarchy and purchases and issues of Level 3 assets and liabilities; (2) for investments in certain entities that calculate net asset value, an entity is required to disclose the timing of liquidation of an investee’s assets and the date when restrictions from redemption might lapse only if the investee has communicated the timing to the entity or announced the timing publicly; and (3) the amendments clarify that the measurement uncertainty disclosure is to communicate information about the uncertainty in measurement as of the reporting date. The following disclosure requirements were added to Topic 820: (1) the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period; (2) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. For certain unobservable inputs, an entity may disclose other quantitative information (such as the median or arithmetic average) in lieu of the weighted average if the entity determines that other quantitative information would be a more reasonable and rational method to reflect the distribution of unobservable inputs used to develop Level 3 fair value measurements. The amendments in this update are effective for annual periods and interim periods within those annual periods beginning after December 15, 2019. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Early adoption is permitted upon issuance of this update. An entity is permitted to early adopt any removed or modified disclosures upon issuance of this update and delay adoption of the additional disclosures until their effective date. The Company is currently evaluating the impact of adopting the new guidance on the Consolidated Financial Statements, but it is not expected to have a material impact.

Trading Securities (Tables)

Trading Securities (Tables)	12 Months Ended
	Dec. 31, 2018
Investments Debt And Equity Securities [Abstract]
Trading Securities Portfolio Realized and Unrealized Gains and Losses	A list of the activity in this portfolio for 2018 and 2017 is summarized below. 2018 2017 Beginning balance $ 6,777 $ 12,383 Purchases 254,555 230,074 Proceeds from sales (259,652 ) (235,922 ) Net realized gain on sales 20 195 Mark-to- market adjustment 37 47 Ending balance $ 1,737 $ 6,777

Investment Debt Securities (Tab

Investment Debt Securities (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value of Available for Sale Securities and Related Gross Unrealized Gains and Losses Recognized in Accumulated Other Comprehensive Income (Loss)	The fair value of available for sale securities and the related gross unrealized gains and losses recognized in accumulated other comprehensive income (loss) were as follows: December 31, 2018 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value Corporate debt securities $ 6,265 $ 162 $ — $ 6,427 Obligations of U.S. government sponsored entities and agencies 38,794 7 933 37,868 Mortgage backed securities 1,623,906 3,792 33,423 1,594,275 Municipal securities 88,415 698 335 88,778 Total available for sale debt securities $ 1,757,380 $ 4,659 $ 34,691 $ 1,727,348 December 31, 2017 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value U.S. Treasury securities $ 5,000 $ 200 $ — $ 5,200 Obligations of U.S. government sponsored entities and agencies 10,000 — 426 9,574 Mortgage backed securities 982,565 752 10,706 972,611 Municipal securities 71,961 863 66 72,758 Total available for sale debt securities $ 1,069,526 $ 1,815 $ 11,198 $ 1,060,143
Schedule of Sales of Available for Sale Securities	Sales of available for sale securities were as follows: 2018 2017 2016 Proceeds $ 355,652 $ 312,692 $ 142,075 Gross gains $ 68 $ 740 $ 13 Gross losses $ 90 $ 747 $ —
Fair Value of Held to Maturity Securities and Related Gross Unrecognized Gains and Losses	The following reflects the fair value of held to maturity securities and the related gross unrecognized gains and losses as of December 31, 2018 and 2017. December 31, 2018 Gross Gross Amortized Unrecognized Unrecognized Fair Cost Gains Losses Value Mortgage backed securities $ 84,983 $ — $ 2,462 $ 82,521 Municipal securities 131,850 799 2,991 129,658 Total held to maturity debt securities $ 216,833 $ 799 $ 5,453 $ 212,179 December 31, 2017 Gross Gross Amortized Unrecognized Unrecognized Fair Cost Gains Losses Value Mortgage backed securities $ 100,039 $ — $ 1,068 $ 98,971 Municipal securities 132,360 1,781 1,497 132,644 Total held to maturity debt securities $ 232,399 $ 1,781 $ 2,565 $ 231,615
Available-for-sale Securities [Member]
Fair Value and Amortized Cost of Investment Securities by Contractual Maturity	The fair value and amortized cost of available for sale debt securities at year end 2018 by contractual maturity were as follows. Mortgage-backed securities are not due at a single maturity date and are shown separately. Fair Amortized Available for sale debt securities: Value Cost Due in one year or less $ 967 $ 966 Due after one year through five years 6,080 6,038 Due after five years through ten years 30,997 31,396 Due after ten years through thirty years 95,029 95,074 Mortgage backed securities 1,594,275 1,623,906 Total available for sale debt securities $ 1,727,348 $ 1,757,380
Investments Gross Unrealized Losses and Fair Value	The following tables show the Company’s investments’ gross unrealized losses and fair value, aggregated by investment category and length of time the individual securities have been in a continuous unrealized loss position, at December 31, 2018 and 2017. December 31, 2018 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses Obligations of U.S. government sponsored entities and agencies $ 25,104 $ 332 $ 9,398 $ 601 $ 34,502 $ 933 Mortgage backed securities 647,923 10,782 635,172 22,641 1,283,095 33,423 Municipal securities 25,031 316 3,381 19 28,412 335 Total temporarily impaired available for sale debt securities $ 698,058 $ 11,430 $ 647,951 $ 23,261 $ 1,346,009 $ 34,691 December 31, 2017 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses Obligations of U.S. government sponsored entities and agencies $ — $ — $ 9,574 $ 426 $ 9,574 $ 426 Mortgage backed securities 477,925 3,298 316,066 7,408 793,991 10,706 Municipal securities 11,698 66 — — 11,698 66 Total temporarily impaired available for sale debt securities $ 489,623 $ 3,364 $ 325,640 $ 7,834 $ 815,263 $ 11,198
Held-to-maturity Securities [Member]
Fair Value and Amortized Cost of Investment Securities by Contractual Maturity	The fair value and amortized cost of held to maturity debt securities at year end 2018 by contractual maturity were as follows. Mortgage-backed securities are not due at a single maturity date and are shown separately. Amortized Held to maturity debt securities Fair Value Cost Due after five years through ten years $ 2,051 $ 2,045 Due after ten years through thirty years 127,607 129,805 Mortgage backed securities 82,521 84,983 Total held to maturity debt securities $ 212,179 $ 216,833
Investments Gross Unrealized Losses and Fair Value	The following tables show the Company’s held to maturity debt investments’ gross unrecognized losses and fair value, aggregated by investment category and length of time the individual securities have been in a continuous unrecognized loss position, at December 31, 2018 and 2017. December 31, 2018 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses Mortgage backed securities $ — $ — $ 82,521 $ 2,462 $ 82,521 $ 2,462 Municipal securities 22,560 203 47,807 2,788 70,367 2,991 Total temporarily impaired held to maturity debt securities $ 22,560 $ 203 $ 130,328 $ 5,250 $ 152,888 $ 5,453 December 31, 2017 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses Mortgage backed securities $ 57,266 $ 451 $ 41,705 $ 617 $ 98,971 $ 1,068 Municipal securities 13,350 186 37,963 1,311 51,313 1,497 Total temporarily impaired held to maturity debt securities $ 70,616 $ 637 $ 79,668 $ 1,928 $ 150,284 $ 2,565

Loans Held for Sale (Tables)

Loans Held for Sale (Tables)	12 Months Ended
	Dec. 31, 2018
Loans Receivable Held For Sale Net [Abstract]
Summary of Activity in Mortgage Loans Held for Sale	The table below summarizes the activity in mortgage loans held for sale for the years ended December 31, 2018 and 2017. December 31, 2018 2017 Beginning balance $ 19,647 $ 2,285 Effect from acquisitions 8,959 — Loans originated 403,492 93,642 Proceeds from sales (403,583 ) (77,791 ) Change in fair value 1,081 — Net realized gain on sales 10,803 1,511 Ending balance $ 40,399 $ 19,647
Summary of Notional Amounts for Interest Rate Lock Commitments and Best Efforts Forward Trades and MBS Forward Trades Pertaining to Loans Held for Sale	The table below summarizes the notional amounts for interest rate lock commitments, best efforts forward trades and MBS forward trades pertaining to loans held for sale at December 31, 2018. Notional Interest rate lock commitments $ 49,545 Best efforts forward trades 61,865 MBS forward trades 30,000 Total derivative instruments $ 141,410

Loans (Tables)

Loans (Tables)	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Summary of Information Concerning Loan Portfolio by Collateral Types	The following table sets forth information concerning the loan portfolio by collateral types as of December 31, 2018 and 2017 are: December 31, 2018 December 30, 2017 Loans excluding PCI loans Real estate loans Residential $ 1,702,114 $ 1,025,303 Commercial 4,454,098 2,546,143 Land, development and construction 635,562 235,816 Total real estate 6,791,774 3,807,262 Commercial 1,183,380 693,501 Consumer and other loans 203,686 107,480 Loans before unearned fees and deferred cost 8,178,840 4,608,243 Net unearned fees and costs 2,693 820 Total loans excluding PCI loans 8,181,533 4,609,063 PCI loans (note 1) Real estate loans Residential 58,804 59,975 Commercial 87,336 92,791 Land, development and construction 7,028 6,656 Total real estate 153,168 159,422 Commercial 5,594 4,444 Consumer and other loans 209 292 Total PCI loans 158,971 164,158 Total loans 8,340,504 4,773,221 Allowance for loan losses for loans that are not PCI loans (39,579 ) (32,530 ) Allowance for loan losses for PCI loans (191 ) (295 ) Total loans, net of allowance for loan losses $ 8,300,734 $ 4,740,396 Note 1: Purchased credit-impaired (“PCI”) loans are being accounted for pursuant to ASC Topic 310-30.
Summary of Allowance for Loan Losses and Recorded Investment in Loans by Portfolio	The following tables present the activity in the allowance for loan losses by portfolio segment for the years ended December 31, 2018, 2017 and 2016. Real Estate Loans Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses for loans that are not PCI loans: Twelve months ended December 31, 2018 Beginning of the period $ 6,003 $ 19,304 $ 1,179 $ 4,130 $ 1,914 $ 32,530 Charge-offs (516 ) (13 ) (126 ) (1,474 ) (1,706 ) (3,835 ) Recoveries 1,027 679 39 360 327 2,432 Provision for loan losses (996 ) 3,008 689 3,398 2,353 8,452 Balance at end of period $ 5,518 $ 22,978 $ 1,781 $ 6,414 $ 2,888 $ 39,579 Twelve months ended December 31, 2017 Beginning of the period $ 5,640 $ 14,713 $ 883 $ 3,785 $ 1,548 $ 26,569 Charge-offs (254 ) (74 ) — (677 ) (994 ) (1,999 ) Recoveries 950 662 596 334 217 2,759 Provision for loan losses (333 ) 4,003 (300 ) 688 1,143 5,201 Balance at end of period $ 6,003 $ 19,304 $ 1,179 $ 4,130 $ 1,914 $ 32,530 Twelve months ended December 31, 2016 Beginning of the period $ 6,015 $ 10,559 $ 936 $ 3,212 $ 1,421 $ 22,143 Charge-offs (290 ) (1,190 ) (232 ) (186 ) (849 ) (2,747 ) Recoveries 1,220 625 269 325 189 2,628 Provision for loan losses (1,305 ) 4,719 (90 ) 434 787 4,545 Balance at end of period $ 5,640 $ 14,713 $ 883 $ 3,785 $ 1,548 $ 26,569 Real Estate Loans Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses for loans that are PCI loans: Twelve months ended December 31, 2018 Beginning of the period $ — $ 59 $ 222 $ — $ 14 $ 295 Charge-offs — — — (10 ) — (10 ) Recoveries — — — 75 — 75 Provision for loan losses — (59 ) (45 ) (65 ) — (169 ) Balance at end of period $ — $ — $ 177 $ — $ 14 $ 191 Twelve months ended December 31, 2017 Beginning of the period $ 54 $ 92 $ 312 $ — $ 14 $ 472 Charge-offs — — — — — — Recoveries — 66 — — — 66 Provision for loan losses (54 ) (99 ) (90 ) — — (243 ) Balance at end of period $ — $ 59 $ 222 $ — $ 14 $ 295 Twelve months ended December 31, 2016 Beginning of the period $ — $ 103 $ 1 $ 3 $ 14 $ 121 Charge-offs — — (66 ) — — (66 ) Recoveries — — — — — — Provision for loan losses 54 (11 ) 377 (3 ) — 417 Balance at end of period $ 54 $ 92 $ 312 $ — $ 14 $ 472
Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method	The following table presents the balance in the allowance for loan losses and the recorded investment in loans by portfolio segment and based on impairment method as of December 31, 2018 and 2017. Accrued interest receivable and unearned fees/costs are not included in the recorded investment because they are not material. Real Estate Loans As of December 31, 2018 Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 331 $ 250 $ — $ 1,034 $ 1 $ 1,616 Collectively evaluated for impairment 5,187 22,728 1,781 5,380 2,887 37,963 Purchased credit-impaired — — 177 — 14 191 Total ending allowance balance $ 5,518 $ 22,978 $ 1,958 $ 6,414 $ 2,902 $ 39,770 Loans: Individually evaluated for impairment $ 6,234 $ 7,496 $ 117 $ 1,708 $ 145 $ 15,700 Collectively evaluated for impairment 1,695,880 4,446,602 635,445 1,181,672 203,541 8,163,140 Purchased credit-impaired 58,804 87,336 7,028 5,594 209 158,971 Total ending loan balances $ 1,760,918 $ 4,541,434 $ 642,590 $ 1,188,974 $ 203,895 $ 8,337,811 Real Estate Loans As of December 31, 2017 Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 586 $ — $ 4 $ 206 $ 8 $ 804 Collectively evaluated for impairment 5,417 19,304 1,175 3,924 1,906 31,726 Purchased credit-impaired — 59 222 — 14 295 Total ending allowance balance $ 6,003 $ 19,363 $ 1,401 $ 4,130 $ 1,928 $ 32,825 Loans: Individually evaluated for impairment $ 8,101 $ 8,218 $ 331 $ 3,497 $ 198 $ 20,345 Collectively evaluated for impairment 1,017,202 2,537,925 235,485 690,004 107,282 4,587,898 Purchased credit-impaired 59,975 92,791 6,656 4,444 292 164,158 Total ending loan balance $ 1,085,278 $ 2,638,934 $ 242,472 $ 697,945 $ 107,772 $ 4,772,401
Summary of Impaired Loans	The following is a summary of information regarding impaired loans at December 31, 2018 and 2017: December 31, 2018 2017 Performing TDRs (these are not included in non-performing loans ("NPLs")) $ 8,475 $ 12,081 Non-performing TDRs (these are included in NPLs) 1,002 698 Total TDRs (these are included in impaired loans) 9,477 12,779 Impaired loans that are not TDRs 6,223 7,566 Total impaired loans $ 15,700 $ 20,345
Troubled Debt Restructured Loans by Loans Type	TDRs as of December 31, 2018 and 2017 quantified by loan type classified separately as accrual (performing loans) and non-accrual (non-performing loans) are presented in the table below. As of December 31, 2018 Accruing Non-Accrual Total Real estate loans: Residential $ 5,848 $ 386 $ 6,234 Commercial 1,837 566 2,403 Land, development, construction 77 41 118 Total real estate loans 7,762 993 8,755 Commercial 577 — 577 Consumer and other 136 9 145 Total TDRs $ 8,475 $ 1,002 $ 9,477 As of December 31, 2017 Accruing Non-Accrual Total Real estate loans: Residential $ 7,737 $ 364 $ 8,101 Commercial 3,286 306 3,592 Land, development, construction 332 — 332 Total real estate loans 11,355 670 12,025 Commercial 556 — 556 Consumer and other 170 28 198 Total TDRs $ 12,081 $ 698 $ 12,779
Summary of Loans by Class Modified	The following table presents loans by class modified as TDRs for which there was a payment default within twelve months following the modification during the years ending December 31, 2018, 2017 and 2016. Period Ending Period Ending Period Ending December 31, 2018 December 31, 2017 December 31, 2016 Number Recorded Number Recorded Number Recorded of loans investment of loans investment of loans investment Residential — $ — — $ — 2 $ 167 Commercial real estate 1 433 1 177 2 936 Land, development, construction 1 49 — — — — Commercial and Industrial — — — — — — Consumer and other — — — — — — Total 2 $ 482 1 $ 177 4 $ 1,103
Summary of Loans Individually Evaluated for Impairment by Class of Loans	The following tables present loans individually evaluated for impairment by class of loans as of December 31, 2018 and 2017 excluding purchased credit-impaired loans accounted for pursuant to ASC Topic 310-30. The recorded investment is less than the unpaid principal balance primarily due to partial charge-offs. As of December 31, 2018 Unpaid principal balance Recorded investment Allowance for loan losses allocated With no related allowance recorded: Residential real estate $ 3,608 $ 3,485 $ — Commercial real estate 6,447 5,906 — Land, development, construction 144 117 — Commercial and industrial 364 353 — Consumer, other 109 108 — With an allowance recorded: Residential real estate 2,897 2,749 331 Commercial real estate 1,593 1,590 250 Land, development, construction — — — Commercial and industrial 1,378 1,355 1,034 Consumer, other 53 37 1 Total $ 16,593 $ 15,700 $ 1,616 As of December 31, 2017 Unpaid principal balance Recorded investment Allowance for loan losses allocated With no related allowance recorded: Residential real estate $ 4,945 $ 4,818 $ — Commercial real estate 8,973 8,218 — Land, development, construction 260 210 — Commercial and industrial 3,374 2,968 — Consumer, other 142 127 — With an allowance recorded: Residential real estate 3,426 3,283 586 Commercial real estate — — — Land, development, construction 140 121 4 Commercial and industrial 531 529 206 Consumer, other 78 71 8 Total $ 21,869 $ 20,345 $ 804
Summary of Impairment by Class of Loans	December 31, 2018 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 7,492 $ 308 $ — Commercial 7,876 104 — Land, development, construction 588 8 — Total real estate loans 15,956 420 — Commercial and industrial 2,081 $ 33 — Consumer and other loans 174 8 — Total $ 18,211 $ 461 $ — December 31, 2017 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 7,731 $ 267 $ — Commercial 8,956 145 — Land, development, construction 432 18 — Total real estate loans 17,119 430 — Commercial and industrial 1,968 29 — Consumer and other loans 240 10 — Total $ 19,327 $ 469 $ — December 31, 2016 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 8,384 $ 257 $ — Commercial 11,696 131 — Land, development, construction 1,503 24 — Total real estate loans 21,583 412 — Commercial and industrial 1,808 44 — Consumer and other loans 253 11 — Total $ 23,644 $ 467 $ —
Summary of Recorded Investment in Non-accrual Loans and Loans Past Due Over 90 Days Still on Accrual by Class of Loans	The following tables present the recorded investment in non-accrual loans and loans past due over 90 days still on accrual by class of loans as of December 31, 2018 and 2017 excluding purchased credit-impaired loans accounted for pursuant to ASC Topic 310-30: As of December 31, 2018 Non-accrual Loans past due over 90 days still accruing Residential real estate $ 11,488 $ — Commercial real estate 8,445 — Land, development, construction 795 — Commercial 2,274 — Consumer, other 565 — Total $ 23,567 $ — As of December 31, 2017 Non-accrual Loans past due over 90 days still accruing Residential real estate $ 7,107 $ — Commercial real estate 6,549 — Land, development, construction 138 — Commercial 3,121 — Consumer, other 373 — Total $ 17,288 $ —
Summary Aging of Recorded Investment in Past Due Loans	The following tables present the aging of the recorded investment in past due loans as of December 31, 2018 and 2017, excluding purchased credit-impaired loans accounted for pursuant to ASC Topic 310-30: Accruing Loans Total 30 - 59 days past due 60 - 89 days past due Greater than 90 days past due Total Past Due Loans Not Past Due Non-accrual Loans As of December 31, 2018 Residential real estate $ 1,702,114 $ 5,730 $ 5,631 $ — $ 11,360 $ 1,679,266 $ 11,488 Commercial real estate 4,454,098 10,840 4,607 — 15,446 4,430,207 8,445 Land/dev/construction 635,562 661 4,022 — 4,683 630,084 795 Commercial 1,183,380 2,803 878 — 3,681 1,177,425 2,274 Consumer 203,686 1,061 271 — 1,332 201,789 565 $ 8,178,840 $ 21,094 $ 15,408 $ — $ 36,502 $ 8,118,771 $ 23,567 Accruing Loans Total 30 - 59 days past due 60 - 89 days past due Greater than 90 days past due Total Past Due Loans Not Past Due Non-accrual Loans As of December 31, 2017 Residential real estate $ 1,025,303 $ 3,568 $ 1,821 $ — $ 5,389 $ 1,012,807 $ 7,107 Commercial real estate 2,546,143 1,158 2,272 — 3,430 2,536,164 6,549 Land/dev/construction 235,816 2,807 189 — 2,996 232,682 138 Commercial 693,501 568 763 — 1,331 689,049 3,121 Consumer 107,480 471 48 — 519 106,588 373 $ 4,608,243 $ 8,572 $ 5,093 $ — $ 13,665 $ 4,577,290 $ 17,288
Risk Category of Loans by Class of Loans, Excluding Purchased Credit Impaired Loans	As of December 31, 2018 Loan Category Pass Special Mention Substandard Doubtful Residential real estate $ 1,633,810 $ 41,522 $ 26,782 $ — Commercial real estate 4,246,687 160,981 46,430 — Land/dev/construction 610,631 20,586 4,345 — Commercial 1,137,272 40,836 5,272 — Consumer 202,701 247 738 — Total $ 7,831,100 $ 264,172 $ 83,568 $ — As of December 31, 2017 Loan Category Pass Special Mention Substandard Doubtful Residential real estate $ 987,472 $ 20,435 $ 17,396 $ — Commercial real estate 2,411,085 115,942 19,116 — Land/dev/construction 217,555 17,699 562 — Commercial 674,764 14,186 4,551 — Consumer 106,735 139 606 — Total $ 4,397,611 $ 168,401 $ 42,231 $ —
Investment in Residential and Consumer Loans, Excluding Loans from Purchased Credit Impaired Loans	The following table presents the recorded investment in residential and consumer loans, excluding purchased credit-impaired loans accounted for pursuant to ASC Topic 310-30, based on payment activity as of December 31, 2018 and 2017: As of December 31, 2018 Residential Consumer Performing 1,690,626 203,121 Non-performing 11,488 565 Total 1,702,114 203,686 As of December 31, 2017 Residential Consumer Performing $ 1,018,196 $ 107,107 Non-performing 7,107 373 Total $ 1,025,303 $ 107,480
Summary of Total Contractually Required Principal and Interest Cash Payments, Management's Estimate of Expected Total Cash Payments and Carrying Value of Loans	The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and carrying value of the loans as of December 31, 2018, 2017 and 2016. Contractually required principal and interest payments have been adjusted for estimated prepayments. December 31, 2018 2017 2016 Contractually required principal and interest $ 267,815 $ 248,283 $ 297,821 Non-accretable difference (38,602 ) (13,183 ) (18,372 ) Cash flows expected to be collected 229,213 235,100 279,449 Accretable yield (70,242 ) (70,942 ) (93,525 ) Carrying value of acquired loans 158,971 164,158 185,924 Allowance for loan losses (191 ) (295 ) (472 ) Carrying value less allowance for loan losses $ 158,780 $ 163,863 $ 185,452
Summary of Changes in Total Contractually Required Principal and Interest Cash Payments	The table below summarizes the changes in total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and carrying value of the loans during the periods ending December 31, 2018, 2017 and 2016. Effect of income all other December 31, 2017 acquisitions accretion adjustments December 31, 2018 Contractually required principal and interest $ 248,283 $ 122,392 $ — $ (102,860 ) $ 267,815 Non-accretable difference (13,183 ) (58,927 ) — 33,508 (38,602 ) Cash flows expected to be collected 235,100 63,465 — (69,352 ) 229,213 Accretable yield (70,942 ) (7,770 ) 35,944 (27,474 ) (70,242 ) Carry value of acquired loans $ 164,158 $ 55,695 $ 35,944 $ (96,826 ) $ 158,971 Effect of income all other December 31, 2016 acquisitions accretion adjustments December 31, 2017 Contractually required principal and interest $ 297,821 $ 31,334 $ — $ (80,872 ) $ 248,283 Non-accretable difference (18,372 ) (7,104 ) — 12,293 (13,183 ) Cash flows expected to be collected 279,449 24,230 — (68,579 ) 235,100 Accretable yield (93,525 ) (4,185 ) 32,388 (5,620 ) (70,942 ) Carry value of acquired loans $ 185,924 $ 20,045 $ 32,388 $ (74,199 ) $ 164,158 Effect of income all other December 31, 2015 acquisitions accretion adjustments December 31, 2016 Contractually required principal and interest $ 332,570 $ 73,005 $ — $ (107,754 ) $ 297,821 Non-accretable difference (19,452 ) (9,295 ) — 10,375 (18,372 ) Cash flows expected to be collected 313,118 63,710 — (97,379 ) 279,449 Accretable yield (102,590 ) (18,585 ) 34,006 (6,356 ) (93,525 ) Carry value of acquired loans $ 210,528 $ 45,125 $ 34,006 $ (103,735 ) $ 185,924

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	12 Months Ended
	Dec. 31, 2018
Real Estate [Abstract]
Activity of Valuation Allowance in Other Real Estate Owned and Expense Related to Foreclosed Assets	Other real estate owned means real estate acquired through or instead of loan foreclosure. Activity in the valuation allowance was as follows: 2018 2017 2016 Beginning of year $ 861 $ 869 $ 1,297 Valuation write down of repossessed real estate 482 682 871 Sales and/or dispositions (939 ) (690 ) (1,299 ) End of year $ 404 $ 861 $ 869 Expenses related to foreclosed real estate include: 2018 2017 2016 Gain on sale of repossessed real estate $ (1,933 ) (876 ) (1,528 ) Valuation write down of repossessed real estate 482 682 871 Operating expenses, net of rental income 2,815 2,252 2,392 Total $ 1,364 $ 2,058 $ 1,735

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis are summarized below. Fair value measurements using Significant Quoted prices in other Significant active markets for observable unobservable Carrying identical assets inputs inputs value (Level 1) (Level 2) (Level 3) at December 31, 2018 Assets: Trading securities $ 1,737 — $ 1,737 — Available for sale debt securities Corporate debt securities 6,427 — 6,427 — Obligations of U.S. government sponsored entities and agencies 37,868 — 37,868 — Mortgage backed securities 1,594,275 — 1,594,275 — Municipal securities 88,778 — 88,778 — Loans held for sale, at fair value 40,399 — 40,399 — Mortgage servicing assets 1,565 — 1,565 — Mortgage banking derivatives 783 — — 783 Interest rate swap derivatives 92,475 — 92,475 — Liabilities: Mortgage banking derivatives 169 — 164 5 Interest rate swap derivatives 92,892 — 92,892 — at December 31, 2017 Assets: Trading securities $ 6,777 — $ 6,777 — Available for sale debt securities U.S. Treasury securities 5,200 — 5,200 — Obligations of U.S. government sponsored entities and agencies 9,574 — 9,574 — Mortgage backed securities 972,611 — 972,611 — Municipal securities 72,758 — 72,758 — Interest rate swap derivatives 42,480 — 42,480 — Liabilities: Interest rate swap derivatives 43,259 — 43,259 —
Assets and Liabilities Measured at Fair Value on Non-Recurring Basis	Assets and liabilities measured at fair value on a non-recurring basis are summarized below. Fair value measurements using Significant Quoted prices in other Significant active markets for observable unobservable Carrying identical assets inputs inputs value (Level 1) (Level 2) (Level 3) at December 31, 2018 Assets: Impaired loans Residential real estate $ 1,811 — — $ 1,811 Commercial real estate 5,614 — — 5,614 Land, land development and construction 90 — — 90 Commercial 1,274 — — 1,274 Consumer 40 — — 40 Other real estate owned Land, land development and construction 867 — — 867 Bank property held for sale 5,805 — — 5,805 at December 31, 2017 Assets: Impaired loans Residential real estate $ 2,423 — — $ 2,423 Commercial real estate 6,293 — — 6,293 Land, land development and construction 292 — — 292 Commercial 2,131 — — 2,131 Consumer 57 — — 57 Other real estate owned Residential real estate 635 — — 635 Commercial real estate 261 — — 261 Land, land development and construction 1,481 — — 1,481 Bank property held for sale 1,516 — — 1,516
Carrying Amounts and Estimated Fair Values of Company's Financial Instruments	The following table presents the carry amounts and estimated fair values of the Company’s financial instruments: Fair value measurements at December 31, 2018 Carrying amount Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents $ 367,333 $ 367,333 $ — $ — $ 367,333 Trading securities 1,737 — 1,737 — 1,737 Available for sale debt securities 1,727,348 — 1,727,348 — 1,727,348 Held to maturity debt securities 216,833 — 212,179 — 212,179 FHLB, FRB and other stock 79,584 — — — n/a Loans held for sale, at fair value 40,399 — 40,399 — 40,399 Loans, net 8,300,734 — — 8,342,220 8,342,220 Mortgage servicing assets 1,565 — 1,565 — 1,565 Mortgage banking derivatives 783 — — 783 783 Interest rate swap derivatives 92,475 — 92,475 — 92,475 Accrued interest receivable 33,143 — 8,355 24,788 33,143 Financial liabilities: Deposits- without stated maturities $ 7,655,376 $ 7,655,376 $ — $ — $ 7,655,376 Deposits- with stated maturities 1,821,960 — 1,827,299 — 1,827,299 Securities sold under agreement to repurchase 57,772 — 57,772 — 57,772 Federal funds purchased and other borrowings 655,360 — 655,360 — 655,360 Corporate debentures 32,415 — — 28,621 28,621 Mortgage banking derivatives 169 — 164 5 169 Interest rate swap derivatives 92,892 — 92,892 — 92,892 Accrued interest payable 2,627 — 2,627 — 2,627 Fair value measurements at December 31, 2017 Carrying amount Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents $ 280,619 $ 280,619 $ — $ — $ 280,619 Trading securities 6,777 — 6,777 — 6,777 Available for sale debt securities 1,060,143 — 1,060,143 — 1,060,143 Held to maturity debt securities 232,399 — 231,615 — 231,615 FHLB, FRB and other stock 34,876 — — — n/a Loans held for sale 19,647 — 19,647 — 19,647 Loans, net 4,740,396 — — 4,731,514 4,731,514 Interest rate swap derivatives 42,480 — 42,480 — 42,480 Accrued interest receivable 18,628 — 5,370 13,258 18,628 Financial liabilities: Deposits- without stated maturities $ 4,727,840 $ 4,727,840 $ — $ — $ 4,727,840 Deposits- with stated maturities 832,683 — 845,039 — 845,039 Securities sold under agreement to repurchase 52,080 — 52,080 — 52,080 Federal funds purchased and other borrowings 331,490 — 331,490 — 331,490 Corporate debentures 26,192 — — 22,363 22,363 Interest rate swap derivatives 43,259 — 43,259 — 43,259 Accrued interest payable 1,169 — 1,169 — 1,169

Bank Premises and Equipment (Ta

Bank Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Summary of Bank Premises and Equipment	A summary of bank premises and equipment as of December 31, 2018 and 2017 is as follows: December 31, 2018 2017 Land $ 72,487 $ 51,724 Land improvements 1,381 1,251 Buildings 130,424 85,625 Leasehold improvements 13,655 6,575 Furniture, fixtures and equipment 45,056 38,662 Construction in progress 15,491 4,783 278,494 188,620 Less: Accumulated depreciation 51,040 46,734 $ 227,454 $ 141,886
Minimum Future Contractual Annual Rentals	The Company leases land and certain facilities under noncancellable operating leases. The following is a schedule of future minimum annual rentals under the noncancellable operating leases: Year ending December 31, 2018 7,113 2019 5,687 2020 5,004 2021 4,274 2022 3,163 Thereafter 15,047 $ 40,288

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Change in Balance for Goodwill	The change in balance for goodwill during the years 2018, 2017 and 2016 is as follows: 2018 2017 2016 Beginning of year $ 257,683 $ 106,028 $ 76,739 Acquired goodwill 545,197 151,655 29,289 Impairment — — — End of year $ 802,880 $ 257,683 $ 106,028
Change in Balance for Core Deposit Intangibles and Trust Intangible Assets	The change in balance for the CDI and Trust intangible assets during the years 2018, 2017 and 2016 is as follows: 2018 2017 2016 Beginning of year $ 24,063 $ 16,209 $ 13,001 Acquired CDI 51,945 12,424 6,282 Amortization expense on CDI and Trust (9,783 ) (3,997 ) (3,074 ) Disposal of Trust intangible asset — (573 ) — End of year $ 66,225 $ 24,063 $ 16,209
Schedule of Core Deposit Intangible and Trust Intangible Assets	CDI and Trust intangible assets for years ended December 31, 2018 and 2017 were as follows: December 31, 2018 December 31, 2017 Gross Gross Carrying Accumulated Carrying Accumulated Amount Amortization Amount Amortization Amortized intangible assets: Core deposit intangibles $ 93,964 $ 27,739 $ 42,019 $ 17,956 Total acquired intangibles $ 93,964 $ 27,739 $ 42,019 $ 17,956
Estimated Amortization Expense	Estimated amortization expense for each of the next five years: CDI 2019 $ 10,479 2020 9,111 2021 7,923 2022 7,245 2023 7,165
Schedule of Activity for Mortgage Servicing Assets Related Valuation Allowance	Activity for MSA and the related valuation allowance follows: 2018 Beginning of year $ — Effect from acquisitions 1,602 Changes in fair value (37 ) End of year $ 1,565
Schedule of Activity for Small Business Administration Servicing Assets	Activity for SBA servicing assets is as follows: 2018 2017 Beginning of year $ 551 $ 85 Additions 846 535 Effect from acquisitions 226 — Amortized to expense (235 ) (69 ) End of year $ 1,388 $ 551

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Summary of Deposits	A detail of deposits at December 31, 2018 and 2017 is as follows: December 31, Weighted Weighted Average Average Interest Interest 2018 Rate 2017 Rate Non-interest bearing deposits $ 2,923,640 — % $ 1,999,901 — % Interest bearing deposits: Interest bearing demand deposits 1,811,006 0.3 % 1,058,985 0.1 % Savings deposits 704,159 0.1 % 501,014 0.1 % Money market accounts 2,216,571 0.9 % 1,167,940 0.4 % Time deposits less than $100,000 871,043 1.6 % 384,347 1.0 % Time deposits of $100,000 or greater 950,917 1.6 % 448,336 1.2 % $ 9,477,336 0.6 % $ 5,560,523 0.3 %
Summary of Certificate Accounts	The following table presents the amount of certificate accounts at December 31, 2018, maturing during the periods reflected below: Year Amount 2019 $ 1,337,688 2020 320,487 2021 89,880 2022 39,552 2023 33,965 Thereafter 388 Total $ 1,821,960

Securities Sold Under Agreeme_2

Securities Sold Under Agreements to Repurchase (Tables)	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Summary of Repurchase Agreement	The following tables provide additional details as of December 31, 2018 and 2017. MBS Municipal As of December 31, 2018 Securities Securities Total Market value of securities pledged $ 64,269 $ 437 $ 64,706 Borrowings related to pledged amounts 57,594 178 57,772 Market value pledged as a % of borrowings 112 % 246 % 112 % MBS Municipal As of December 31, 2017 Securities Securities Total Market value of securities pledged $ 59,239 $ 443 $ 59,682 Borrowings related to pledged amounts 52,030 50 52,080 Market value pledged as a % of borrowings 114 % 886 % 115 % Information concerning repurchase agreements is summarized as follows: 2018 2017 2016 Average daily balance during the year $ 54,344 $ 43,850 $ 29,435 Average interest rate during the year 1.16 % 0.56 % 0.35 % Maximum month-end balance during the year $ 59,751 $ 52,080 $ 35,500 Weighted average interest rate at year end 1.66 % 0.88 % 0.33 %

Federal Funds Purchased (Tables

Federal Funds Purchased (Tables)	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Federal Funds Purchased, Overnight Deposits from Correspondent Banks	Information concerning these deposits is summarized as follows: 2018 2017 2016 Average daily balance during the year $ 250,499 $ 263,669 $ 210,276 Average interest rate during the period 2.02 % 1.13 % 0.55 % Maximum month-end balance during the year $ 294,360 $ 335,531 $ 288,582 Weighted average interest rate at year end 2.07 % 1.39 % 0.72 %

Other Borrowed Funds (Tables)

Other Borrowed Funds (Tables)	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Summary of Advances from Federal Home Loan Bank	From time to time, the Company borrows either through Federal Home Loan Bank advances or one-day borrowings, other than correspondent bank deposits listed in Note 12 above. At year end, advances from the Federal Home Loan Bank were as follows: 2018 2017 Fixed rate advances, maturity through 01/28/2019, rates from 2.45% and 2.54%, averaging 2.50% $ 200,000 $ — Floating rate advances, rates of 2.65% and 1.59%, as of December 31, 2018 and 2017, respectively 150,000 155,000 Total $ 350,000 $ 155,000

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Allocation of Federal and State Income Tax Expense (Benefit) Between Current and Deferred Portions	Allocation of federal and state income tax expense between current and deferred portions for the years ended December 31, 2018, 2017 and 2016, is as follows: Current Deferred Total December 31, 2018: Federal $ 14,273 $ 16,843 $ 31,116 State 5,240 4,668 9,908 $ 19,513 $ 21,511 $ 41,024 December 31, 2017: Federal $ 18,243 $ 29,393 $ 47,636 State 4,045 1,799 5,844 $ 22,288 $ 31,192 $ 53,480 December 31, 2016: Federal $ 15,172 $ 3,127 $ 18,299 State 3,091 520 3,611 $ 18,263 $ 3,647 $ 21,910
Components of Deferred Tax Assets and Deferred Tax Liabilities	The tax effect of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2018 and 2017, are presented below: December 31, 2018 2017 Deferred tax assets: Allowance for loan losses $ 10,079 $ 8,320 Stock based compensation 1,701 1,609 Deferred compensation 2,235 1,488 Impairment expenses 1,334 572 Net operating loss carryforward 18,313 13,278 Other real estate owned expenses 177 557 Fair value adjustments 17,929 13,414 Non-accrual interest 2,890 1,385 Unrealized loss on available for sale debt securities 7,611 2,378 Other — 2,339 Total deferred tax assets 62,269 45,340 Deferred tax liabilities: Premises and equipment, due to differences in depreciation methods and useful lives (8,145 ) (5,441 ) Deferred loan costs, net (683 ) (208 ) Prepaid expenses (1,608 ) (1,752 ) Like kind exchange (197 ) (197 ) Accretion of discounts on investments (67 ) (17 ) Other (107 ) — Total deferred tax liabilities (10,807 ) (7,615 ) Net deferred tax asset $ 51,462 $ 37,725
Summary of Net Operating Loss Carryforwards	At December 31, 2018, total net operating losses approximate $71,483, which includes $19,653 from 2018. Effective January 1, 2018, net operating losses generated on January 1, 2018 and forward are no longer subject to a 20-year carryforward period and are carried indefinitely until fully utilized. Excluding the net operating losses not subject to expiration, the Company had approximately $51,830 of net operating loss carryforwards at December 31, 2018, which will begin to expire as follows: 2027 $ 2,418 2028 1,996 2029 11,826 2030 13,681 2031 7,246 2032 6,841 2033 7,063 2035 759 $ 51,830
Reconciliation Between the Actual Tax Expense and the Expected Tax (Benefit) Expense	A reconciliation between the actual tax expense and the “expected” tax expense, computed by applying the U.S. federal corporate rate of 21 percent for 2018 and 35 percent for 2017 and 2016 is as follows: December 31, 2018 2017 2016 “Expected” tax expense $ 41,466 $ 38,246 $ 22,488 Tax exempt interest, net (3,177 ) (4,104 ) (2,364 ) Bank owned life insurance (1,167 ) (1,251 ) (825 ) State income taxes, net of federal income tax benefits 7,827 4,077 2,347 Stock based compensation 17 40 81 Merger and acquisition related expenses 610 1,049 388 Excess tax benefit from stock based compensation (5,095 ) (3,007 ) — Revaluation of net deferred tax asset due to change in federal income tax rate — 18,575 — Other, net 543 (145 ) (205 ) $ 41,024 $ 53,480 $ 21,910

Related-Party Transactions (Tab

Related-Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Summary Loans to Principal Officers, Directors and Their Affiliates	Loans to principal officers, directors, and their affiliates during 2017 and 2016 were as follows: 2018 2017 Beginning balance $ 30,458 $ 26,515 New loans and advances on existing loans 39,183 21,753 Repayments (21,215 ) (17,810 ) Ending balance $ 48,426 $ 30,458

Regulatory Capital Matters (Tab

Regulatory Capital Matters (Tables)	12 Months Ended
	Dec. 31, 2018
Banking And Thrift [Abstract]
Summary of Actual, Required, and Capital Levels Necessary for Capital Adequacy Purposes	A summary of actual, required, and capital levels necessary for capital adequacy purposes for the Company as of December 31, 2018 and 2017, are presented in the table below. The ratios for capital adequacy purposes do not include capital conservation buffer requirements. To be well capitalized under For capital prompt corrective Actual adequacy purposes action provision Amount Ratio Amount Ratio Amount Ratio December 31, 2018 Total capital (to risk weighted assets) $ 1,183,229 12.7% $ 745,543 >8.0% n/a n/a Tier 1 capital (to risk weighted assets) 1,143,459 12.3% 559,157 >6.0% n/a n/a Common equity tier 1 capital (to risk weighted assets) 1,104,959 11.9% 419,368 >4.5% n/a n/a Tier 1 capital (to average assets) 1,143,459 10.0% 455,561 >4.0% n/a n/a December 31, 2017 Total capital (to risk weighted assets) $ 682,175 12.6% $ 434,245 >8.0% n/a n/a Tier 1 capital (to risk weighted assets) 649,350 12.0% 325,684 >6.0% n/a n/a Common equity tier 1 capital (to risk weighted assets) 621,956 11.5% 244,263 >4.5% n/a n/a Tier 1 capital (to average assets) 649,350 9.8% 264,616 >4.0% n/a n/a A summary of actual, required, and capital levels necessary for capital adequacy purposes in the case of the Company’s subsidiary bank as of December 31, 2018 and 2017, are presented in the table below. The ratios for capital adequacy purposes do not include capital conservation buffer requirements. To be well capitalized under For capital prompt corrective Actual adequacy purposes action provision Amount Ratio Amount Ratio Amount Ratio December 31, 2018 Total capital (to risk weighted assets) $ 1,177,082 12.6% $ 745,003 >8.0% $ 931,254 >10.0% Tier 1 capital (to risk weighted assets) $ 1,137,315 12.2% 558,753 >6.0% 745,003 >8.0% Common equity tier 1 capital (to risk weighted assets) $ 1,137,315 12.2% 419,064 >4.5% 605,315 >6.5% Tier 1 capital (to average assets) $ 1,137,315 10.0% 455,515 >4.0% 569,394 >5.0% December 31, 2017 Total capital (to risk weighted assets) $ 654,018 12.2% $ 430,561 >8.0% $ 538,202 >10.0% Tier 1 capital (to risk weighted assets) 621,199 11.5% 322,921 >6.0% 430,561 >8.0% Common equity tier 1 capital (to risk weighted assets) 621,199 11.5% 242,191 >4.5% 349,831 >6.5% Tier 1 capital (to average assets) 621,199 9.4% 264,577 >4.0% 330,721 >5.0%

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Stock Based Compensation Expense Recognized	The Company’s stock-based compensation consists of stock options, RSAs, RSUs and PSUs. During the twelve month period ended December 31, 2018, 2017 and 2016, the Company recognized total stock-based compensation expense as listed in the table below. 2018 2017 2016 Stock option expense $ 83 $ 115 $ 230 RSA expense 2,922 3,560 3,605 RSU Expense 538 287 169 PSU expense 650 624 419 Total stock-based compensation expense $ 4,193 $ 4,586 $ 4,423
Information Related to Stock Option Activity	2018 2017 2016 Total intrinsic value of stock options exercised $ 1,492 $ 8,039 $ 2,716 Net proceeds from stock options exercised $ 14,707 $ 6,715 $ 1,769 Gross income tax benefit from the exercise of stock options $ 5,373 $ 1,545 140
Summary of Stock Option Activity	A summary of stock option activity for the years ended December 31, 2018, 2017 and 2016 is as follows: December 31, 2018 December 31, 2017 December 31, 2016 Weighted- Weighted- Weighted- Average Average Average Number of Exercise Number of Exercise Number of Exercise Options Price Options Price Options Price Outstanding, beginning of period 1,119,483 $ 11.26 623,490 $ 12.30 940,634 $ 11.73 Options assumed pursuant to acquisition of (note 1): Gateway — — 1,150,517 $ 11.32 — — HCBF 1,621,543 $ 14.80 — — — — Sunshine 590,345 $ 14.84 — — — — Exercised (1,793,339 ) $ 13.61 (598,039 ) $ 12.11 (229,583 ) $ 8.74 Forfeited (882,771 ) $ 15.37 (56,485 ) $ 15.00 (87,561 ) $ 15.51 Outstanding, end of period 655,261 $ 11.26 1,119,483 $ 11.26 623,490 $ 12.30
Summary of Outstanding, Vested and Expected to Vest and Exercisable Stock Options	Weighted- Weighted- Average Average Aggregate Number of Exercise Contractual Intrinsic Options Price Term Value Options outstanding, December 31, 2018 655,261 $ 11.26 4.2 years $ 6,412 Options fully vested and expected to vest, December 31, 2018 653,212 $ 11.27 4.2 years $ 6,381 Options exercisable, December 31, 2018 626,401 $ 11.37 4.3 years $ 6,051
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Restricted Stock Awards Activity	A summary of the RSA activity for the years ended December 31, 2018, 2017 and 2016 is presented in the table below. 2018 2017 2016 Number Number Weighted Number Number Weighted Number Number Weighted of RSAs of RSAs average of RSAs of RSAs average of RSAs of RSAs average underlying underlying Total fair value underlying underlying Total fair value underlying underlying Total fair value shares not shares number at grant shares not shares number at grant shares not shares number at grant issued issued of RSAs date issued issued of RSAs date issued issued of RSAs date Outstanding, beginning period 489,424 69,700 559,124 $ 15.89 572,064 127,901 699,965 $ 12.20 532,127 189,588 721,715 $ 10.79 Granted 67,502 — 67,502 $ 26.77 148,232 — 148,232 $ 24.94 262,934 — 262,934 $ 14.68 Vested (214,847 ) (19,100 ) (233,947 ) $ 13.65 (226,606 ) (58,201 ) (284,807 ) $ 11.52 (219,032 ) (60,087 ) (279,119 ) $ 10.88 Forfeited (2,313 ) — (2,313 ) $ 18.55 (4,266 ) — (4,266 ) $ 15.76 (3,965 ) (1,600 ) (5,565 ) $ 12.07 Outstanding, end of period 339,766 50,600 390,366 $ 19.10 489,424 69,700 559,124 $ 15.89 572,064 127,901 699,965 $ 12.20
Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Restricted Stock Units	December 31, 2018 December 31, 2017 December 31, 2016 Weighted Weighted Weighted average average average fair value fair value fair value Number of at grant Number of at grant Number of at grant Units date Units date Units date Outstanding, beginning of period 86,817 $ 17.00 54,376 $ 14.00 29,092 $ 12.22 Granted 41,630 26.60 32,441 22.19 28,725 15.37 Vested and issued — — — — (3,441 ) 12.22 Forfeited — — — — — — Outstanding, end of period 128,447 $ 20.00 86,817 $ 17.00 54,376 $ 14.00

Parent Company Only Financial_2

Parent Company Only Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Condensed Balance Sheet	Condensed financial statements of CenterState Bank Corporation (parent company only) follow: Condensed Balance Sheets December 31, 2018 and 2017 Assets: 2018 2017 Cash and due from banks $ 1,338 $ 1,569 Inter-company receivable from bank subsidiary 2,340 840 Investment in wholly-owned bank subsidiary 1,999,963 903,882 Investment in other wholly-owned subsidiary 2,761 1,951 Prepaid expenses and other assets 10,506 49,011 Total assets $ 2,016,908 $ 957,253 Liabilities: Accounts payable and accrued expenses $ 2,149 $ 6,311 Other borrowings 11,000 20,000 Corporate debentures 32,415 26,192 Total liabilities 45,564 52,503 Stockholders’ Equity: Common stock 957 602 Additional paid-in capital 1,699,031 737,905 Retained earnings 293,777 173,248 Accumulated other comprehensive income (22,421 ) (7,005 ) Total stockholders’ equity 1,971,344 904,750 Total liabilities and stockholders' equity $ 2,016,908 $ 957,253
Condensed Statements of Income	Condensed Statements of Operations Years ended December 31, 2018, 2017 and 2016 2018 2017 2016 Dividend income $ 68,000 $ 10,000 $ 58,000 Other income 8 — 308 Interest expense (3,415 ) (1,363 ) (1,159 ) Operating expenses (3,988 ) (3,960 ) (3,869 ) Income before equity in undistributed income of subsidiaries 60,605 4,677 53,280 Equity in undistributed income (losses) of subsidiaries 88,532 48,760 (12,736 ) Net income before income tax benefit 149,137 53,437 40,544 Income tax benefit (7,298 ) (2,358 ) (1,797 ) Net income $ 156,435 $ 55,795 $ 42,341
Condensed Statements of Cash Flows	Condensed Statements of Cash Flows Years ended December 31, 2018, 2017 and 2016 2018 2017 2016 Cash flows from operating activities: Net income $ 156,435 $ 55,795 $ 42,341 Adjustments to reconcile net income to net cash used in operating activities: Undistributed net (earnings) losses of subsidiaries (88,532 ) (48,760 ) 70,736 Increase in payables and accrued expenses (13,385 ) 463 (25 ) Gain on extinguishment of debt — — (308 ) (Increase) decrease in other assets 3,998 (40,369 ) 84 Stock based compensation expense — 1,048 1,001 Net cash flows provided by (used in) operating activities 58,516 (31,823 ) 113,829 Cash flows from investing activities: Inter-company receivables from subsidiary bank (473 ) 25,145 (58,241 ) Net cash from bank acquisitions (36,037 ) (42,601 ) (38,918 ) Investment in subsidiaries — (25,000 ) 450 Cash payments to shareholders 19,339 (90 ) 39 Net cash flows used in investing activities (17,171 ) (42,546 ) (96,670 ) Cash flows from financing activities: Stock options exercised 14,707 6,715 1,769 Stock repurchase (1,027 ) (1,131 ) (962 ) Stock issuance 650 — — Extinguishment of debt — — (8,680 ) (Decrease) increase in other borrowings (20,000 ) 20,000 (650 ) Proceeds from stock offering, net of offering costs — 63,262 — Dividends paid to shareholders (35,906 ) (13,878 ) (7,681 ) Net cash flows (used in) provided by financing activities (41,576 ) 74,968 (16,204 ) Net increase (decrease) in cash and cash equivalents (231 ) 599 955 Cash and cash equivalents at beginning of year 1,569 970 15 Cash and cash equivalents at end of year $ 1,338 $ 1,569 $ 970

Credit Commitments (Tables)

Credit Commitments (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Summary of Credit Commitments	A summary of commitments to extend credit and standby letters of credit written at December 31, 2018 and 2017, are as follows: December 31, 2018 2017 Standby letters of credit $ 28,964 $ 15,740 Available lines of credit 1,514,359 824,958 Unfunded loan commitments – fixed 153,680 140,750 Unfunded loan commitments – variable 65,880 35,814

Basic and Diluted Earnings Pe_2

Basic and Diluted Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Factors Used in Earnings Per Share Computations	The following table presents the factors used in the earnings per share computations for the periods indicated. 2018 2017 2016 Basic Net income available to common shareholders $ 156,435 $ 55,795 $ 42,341 Less: Earnings allocated to participating securities (116 ) (120 ) (163 ) Net income allocated to common shareholders $ 156,319 $ 55,675 $ 42,178 Weighted average common shares outstanding including participating securities 87,707,196 57,368,322 47,592,500 Less: Participating securities (1) (65,976 ) (123,624 ) (183,358 ) Average shares 87,641,220 57,244,698 47,409,142 Basic earnings per common share $ 1.78 $ 0.97 $ 0.89 Diluted Net income available to common shareholders $ 156,319 $ 55,675 $ 42,178 Weighted average common shares outstanding for basic earnings per common share 87,641,220 57,244,698 47,409,142 Add: Dilutive effects of stock based compensation awards 1,117,633 1,096,115 782,381 Average shares and dilutive potential common shares 88,758,853 58,340,813 48,191,523 Dilutive earnings per common share $ 1.76 $ 0.95 $ 0.88 Note 1. Participating securities are restricted stock awards whereby the stock certificates have been issued, are included in outstanding shares, receive dividends and can be voted, but have not vested.

Reportable Segments (Tables)

Reportable Segments (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Reconciliation of Reportable Segment Revenues, Expenses and Profit	The tables below are reconciliations of the reportable segment revenues, expenses, and profit as viewed by management to the Company’s consolidated total for the year ending December 31, 2018, 2017 and 2016. Year ending December 31, 2018 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 445,688 $ 14,944 $ — — $ 460,632 Interest expense (36,853 ) $ (7,282 ) (3,415 ) — (47,550 ) Net interest income (expense) 408,835 $ 7,662 (3,415 ) — 413,082 Provision for loan losses (7,914 ) $ (369 ) — — (8,283 ) Non-interest income 71,731 $ 33,388 8 — 105,127 Non-interest expense (286,191 ) $ (22,288 ) (3,988 ) — (312,467 ) Net income (loss) before taxes 186,461 $ 18,393 (7,395 ) — 197,459 Income tax (provision) benefit (43,662 ) (4,660 ) 7,298 — (41,024 ) Net income (loss) $ 142,799 $ 13,733 $ (97 ) $ — $ 156,435 Total assets $ 11,769,734 $ 561,885 $ 2,016,908 $ (2,010,939 ) $ 12,337,588 Year ending December 31, 2017 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 240,583 $ 10,743 $ — — $ 251,326 Interest expense (11,431 ) (2,989 ) (1,363 ) — (15,783 ) Net interest income (expense) 229,152 7,754 (1,363 ) — 235,543 Provision for loan losses (5,037 ) 79 — — (4,958 ) Non-interest income 36,834 28,341 — — 65,175 Non-interest expense (161,946 ) (20,579 ) (3,960 ) — (186,485 ) Net income (loss) before taxes 99,003 15,595 (5,323 ) — 109,275 Income tax (provision) benefit (49,823 ) (6,015 ) 2,358 — (53,480 ) Net income (loss) $ 49,180 $ 9,580 $ (2,965 ) $ — $ 55,795 Total assets $ 6,572,636 $ 506,234 $ 957,253 $ (912,148 ) $ 7,123,975 Year ending December 31, 2016 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 180,696 $ 7,969 $ — — $ 188,665 Interest expense (7,044 ) (1,137 ) (1,159 ) — (9,340 ) Net interest income 173,652 6,832 (1,159 ) — 179,325 Provision for loan losses (4,938 ) (24 ) — — (4,962 ) Non-interest income 30,376 33,685 308 — 64,369 Non-interest expense (147,228 ) (23,384 ) (3,869 ) — (174,481 ) Net income before taxes 51,862 17,109 (4,720 ) — 64,251 Income tax (provision) benefit (17,107 ) (6,600 ) 1,797 — (21,910 ) Net income (loss) $ 34,755 $ 10,509 $ (2,923 ) $ — $ 42,341 Total assets $ 4,676,375 $ 397,323 $ 584,572 $ (579,711 ) $ 5,078,559

Business Combinations (Tables)

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2018
Pro-Forma Financial Information of Acquisition	Pro-forma data for the twelve-month period ending December 31, 2017 listed in the table below presents pro-forma information as if the Platinum, Gateway, Sunshine, HCBF and Charter acquisitions occurred at the beginning of 2017. The pro-forma information for the twelve-month period ending December 31, 2018 assumes the Charter acquisition occurred at the beginning of 2017. Years ended December 31, 2018 2017 Net interest income $ 450,847 $ 421,556 Net income available to common shareholders $ 178,746 $ 96,633 EPS - basic $ 1.88 $ 1.04 EPS - diluted $ 1.85 $ 1.02
Platinum Bank Holding Company [Member]
Summary of Purchase Price Calculation	The table below summarizes the purchase price calculation. Number of shares of Platinum common stock exchanged for CenterState common stock 1,131,134 Per share exchange ratio 3.7832 Number of shares of CenterState common stock less 51 of fractional shares 4,279,255 CenterState common stock price per share on March 31, 2017 $ 25.90 Fair value of CenterState common stock issued $ 110,833 Total Platinum common shares 1,131,134 Cash consideration each Platinum share was entitled to receive $ 7.60 Total cash consideration, not including cash for fractional shares $ 8,597 Total stock consideration $ 110,833 Total cash consideration, plus $1 for 51 of fractional shares $ 8,598 Total purchase price $ 119,431
Summary of Preliminary Estimates of Fair Value of Assets Purchased, Including Goodwill and Liabilities Assumed	The list below summarizes the estimates of the fair value of the assets purchased, including goodwill, and liabilities assumed as of the April 1, 2017 purchase date. April 1, 2017 Assets: Cash and cash equivalents $ 106,537 Loans, held for investment 442,366 Purchased credit impaired loans 12,218 Investments 28,873 Accrued interest receivable 1,216 Branch real estate 9,600 Furniture and fixtures 402 Bank property held for sale 4,382 FHLB stock 2,220 Other repossessed real estate owned 272 Core deposit intangible 3,992 Goodwill 73,829 Deferred tax asset 227 Other assets 29 Total assets acquired $ 686,163 Liabilities: Deposits $ 520,423 Federal Home Loan Bank advances 40,546 Securities sold under agreement to repurchase 5,569 Accrued interest payable 94 Other liabilities 100 Total liabilities assumed $ 566,732
Summary of Contractually Required Principal and Interest Cash Payments for Purchased Credit Impaired Loans	The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of April 1, 2017 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 18,811 Non-accretable difference (4,639 ) Cash flows expected to be collected 14,172 Accretable yield (1,954 ) Total purchased credit-impaired loans acquired $ 12,218
Summary of Fair Value of Acquired Loans and Unpaid Principal Balance	The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Balance Fair Value Loans: Single family residential real estate $ 37,206 $ 37,419 Commercial real estate 262,612 259,727 Construction/development/land 47,675 46,618 Commercial loans 96,587 95,701 Consumer and other loans 2,954 2,901 Purchased credit-impaired 16,530 12,218 Total earning assets $ 463,564 $ 454,584
Gateway Financial Holdings Of Florida Inc [Member]
Summary of Purchase Price Calculation	The table below summarizes the purchase price calculation. Number of shares of Gateway common stock outstanding at April 30, 2017 5,463,764 Gateway preferred shares that converted to Gateway common shares upon a change in control 919,236 Total Gateway common shares including conversion of preferred shares 6,383,000 Number of shares of Gateway common shares exchanged for CenterState common stock 4,468,100 Per share exchange ratio 0.95 Number of shares of CenterState common stock less 254 of fractional shares 4,244,441 CenterState common stock price per share on April 30, 2017 $ 25.23 Fair value of CenterState common stock issued $ 107,087 Number of shares of Gateway common shares exchanged for cash 1,914,900 Cash consideration each Gateway share is entitled to receive $ 18.00 Total cash consideration, not including cash for fractional shares $ 34,468 Total stock consideration $ 107,087 Total cash consideration plus $6 for 254 of fractional shares $ 34,474 Total consideration paid to Gateway common shareholders $ 141,561 Fair value of Gateway stock options converted to CenterState stock options $ 15,811 Total purchase price $ 157,372
Summary of Preliminary Estimates of Fair Value of Assets Purchased, Including Goodwill and Liabilities Assumed	The list below summarizes the preliminary estimates of the fair value of the assets purchased, including goodwill, and liabilities assumed as of the May 1, 2017 purchase date. May 1, 2017 Assets: Cash and cash equivalents $ 23,065 Loans, held for investment 560,413 Purchased credit impaired loans 7,827 Investments 231,951 Accrued interest receivable 2,422 Branch real estate 18,160 Furniture and fixtures 702 Bank property held for sale 1,087 FHLB and FRB stock 4,640 Other repossessed real estate owned 134 Bank owned life insurance 15,475 Servicing asset 271 Core deposit intangible 8,432 Goodwill 77,826 Deferred tax asset 7,246 Other assets 1,217 Total assets acquired $ 960,868 Liabilities: Deposits $ 708,209 Federal Home Loan Bank advances 90,598 Federal funds purchased 3,588 Accrued interest payable 304 Other liabilities 797 Total liabilities assumed $ 803,496
Summary of Contractually Required Principal and Interest Cash Payments for Purchased Credit Impaired Loans	The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of May 1, 2017 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 12,523 Non-accretable difference (2,465 ) Cash flows expected to be collected 10,058 Accretable yield (2,231 ) Total purchased credit-impaired loans acquired $ 7,827
Summary of Fair Value of Acquired Loans and Unpaid Principal Balance	The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Fair Balance Value Loans: Single family residential real estate $ 142,881 $ 142,468 Commercial real estate 321,262 317,578 Construction/development/land 47,727 46,489 Commercial loans 46,953 46,274 Consumer and other loans 7,803 7,604 Purchased credit-impaired 11,093 7,827 Total earning assets $ 577,719 $ 568,240
Sunshine Bancorp, Inc. [Member]
Summary of Purchase Price Calculation	The table below summarizes the purchase price calculation. Number of shares of Sunshine common stock outstanding at December 31, 2017 7,922,479 Per share exchange ratio 0.89 Number of shares of CenterState common stock less 361 of fractional shares 7,050,645 CenterState common stock price per share on December 29, 2017 $ 25.73 Fair value of CenterState common stock issued $ 181,413 Cash consideration paid for 361 of fractional shares 7 Total consideration to be paid to Sunshine common shareholders $ 181,420 Fair value of Sunshine stock options converted to CenterState stock options 6,432 Total Purchase Price for Sunshine $ 187,852
Summary of Contractually Required Principal and Interest Cash Payments for Purchased Credit Impaired Loans	The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of January 1, 2018 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 21,598 Non-accretable difference (12,213 ) Cash flows expected to be collected 9,385 Accretable yield (1,153 ) Total purchased credit-impaired loans acquired $ 8,232
Summary of Fair Value of Acquired Loans and Unpaid Principal Balance	The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Fair Balance Value Loans: Single family residential real estate $ 148,342 $ 146,057 Commercial real estate 375,377 371,323 Construction/development/land 58,530 57,331 Commercial loans 104,811 99,650 Consumer and other loans 1,770 1,729 Purchased credit-impaired 18,149 8,232 Total earning assets $ 706,979 $ 684,322
Summary of Fair Value of Assets Purchased, Including Goodwill and Liabilities Assumed	The list below summarizes the fair value of the assets purchased, including goodwill, and liabilities assumed as of the January 1, 2018 purchase date. January 1, 2018 Assets: Cash and cash equivalents $ 47,056 Loans, held for investment 676,090 Purchased credit impaired loans 8,232 Loans held for sale 430 Investments 93,006 Accrued interest receivable 2,170 Branch real estate 9,375 Furniture and fixtures 916 Bank property held for sale 9,503 FHLB stock 4,875 Bank owned life insurance 23,101 Core deposit intangible 8,525 Goodwill 114,228 Deferred tax asset 11,890 Other assets 5,915 Total assets acquired $ 1,015,312 Liabilities: Deposits $ 719,039 Federal Home Loan Bank advances 95,001 Securities sold under agreement to repurchase 353 Subordinated notes 11,000 Accrued interest payable 457 Other liabilities 1,610 Total liabilities assumed $ 827,460
HCBF Holding Company, Inc. [Member]
Summary of Purchase Price Calculation	The table below summarizes the purchase price calculation. Number of shares of HCBF common stock outstanding at December 31, 2017 22,299,082 Per share exchange ratio 0.675 Number of shares of CenterState common stock less 241 of fractional shares 15,051,639 CenterState common stock price per share on December 29, 2017 $ 25.73 Fair value of CenterState common stock issued $ 387,279 Number of shares of HCBF common stock outstanding at December 31, 2017 22,299,082 Cash consideration each HCBF share is entitled to receive $ 1.925 Total Cash Consideration plus $6 for 241 of fractional shares $ 42,932 Total Stock Consideration $ 387,279 Total Cash Consideration 42,932 Total consideration to be paid to HCBF common shareholders $ 430,211 Fair value of HCBF stock options converted to CenterState stock options $ 18,025 Total Purchase Price for HCBF $ 448,236
Summary of Contractually Required Principal and Interest Cash Payments for Purchased Credit Impaired Loans	The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of January 1, 2018 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 67,107 Non-accretable difference (25,951 ) Cash flows expected to be collected 41,156 Accretable yield (5,125 ) Total purchased credit-impaired loans acquired $ 36,031
Summary of Fair Value of Acquired Loans and Unpaid Principal Balance	The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Fair Balance Value Loans: Single family residential real estate $ 370,611 $ 363,559 Commercial real estate 636,517 627,900 Construction/development/land 149,547 146,639 Commercial loans 113,818 110,630 Consumer and other loans 41,660 41,276 Purchased credit-impaired 54,320 36,031 Total earning assets $ 1,366,473 $ 1,326,035
Summary of Fair Value of Assets Purchased, Including Goodwill and Liabilities Assumed	The list below summarizes the fair value of the assets purchased, including goodwill, and liabilities assumed as of the January 1, 2018 purchase date. January 1, 2018 Assets: Cash and cash equivalents $ 77,176 Loans, held for investment 1,290,004 Purchased credit impaired loans 36,031 Loans held for sale 5,694 Investments 585,297 Accrued interest receivable 5,847 Branch real estate 34,035 Furniture and fixtures 3,571 Bank property held for sale 14,140 FHLB and other stock 9,488 Bank owned life insurance 39,089 Other real estate owned 5,144 Core deposit intangible 23,625 Goodwill 233,321 Deferred tax asset 14,684 Other assets 1,923 Total assets acquired $ 2,379,069 Liabilities: Deposits $ 1,755,155 Federal Home Loan Bank advances 157,919 Corporate debentures 5,872 Accrued interest payable 478 Other liabilities 11,409 Total liabilities assumed $ 1,930,833
Charter Financial Corporation [Member]
Summary of Purchase Price Calculation	The table below summarizes the purchase price calculation. Number of shares of Charter common stock outstanding at August 31, 2018 15,480,776 Per share exchange ratio 0.738 Number of shares of CenterState common stock less 599 of fractional shares 11,424,214 CenterState common stock price per share on August 31, 2018 $ 30.62 Fair value of CenterState common stock issued $ 349,809 Number of shares of Charter common stock outstanding at August 31, 2018 15,480,776 Cash consideration each Charter share is entitled to receive $ 2.300 Total Cash Consideration plus $17 for 599 of fractional shares $ 35,624 Total Stock Consideration $ 349,809 Total Cash Consideration 35,624 Total consideration to be paid to Charter common shareholders $ 385,433 Cash out of Charter stock options 4,043 Total Purchase Price for Charter $ 389,476
Summary of Contractually Required Principal and Interest Cash Payments for Purchased Credit Impaired Loans	The table below summarizes the total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and fair value of the loans as of September 1, 2018 for purchased credit impaired loans. Contractually required principal and interest payments have been adjusted for estimated prepayments. Contractually required principal and interest $ 33,687 Non-accretable difference (20,763 ) Cash flows expected to be collected 12,924 Accretable yield (1,492 ) Total purchased credit-impaired loans acquired $ 11,432
Summary of Fair Value of Acquired Loans and Unpaid Principal Balance	The table below presents information with respect to the fair value of acquired loans, as well as their unpaid principal balance (“Book Balance”) at acquisition date. Book Fair Balance Value Loans: Single family residential real estate $ 284,505 $ 280,200 Commercial real estate 567,506 557,730 Construction/development/land 181,128 178,687 Commercial loans 88,308 87,062 Consumer and other loans 26,221 26,561 Purchased credit-impaired 17,122 11,432 Total earning assets $ 1,164,790 $ 1,141,672
Summary of Fair Value of Assets Purchased, Including Goodwill and Liabilities Assumed	The list below summarizes the fair value of the assets purchased, including goodwill, and liabilities assumed as of the September 1, 2018 purchase date. September 1, 2018 Assets: Cash and cash equivalents $ 184,020 Loans, held for investment 1,130,240 Purchased credit impaired loans 11,432 Loans held for sale 2,835 Investments 73,808 Accrued interest receivable 3,684 Branch real estate 27,930 Furniture and fixtures 1,988 Bank property held for sale 1,695 FHLB and other stock 1,483 Bank owned life insurance 54,813 Other real estate owned 257 Servicing asset 1,828 Core deposit intangible 19,795 Goodwill 197,648 Deferred tax asset 3,441 Other assets 17,644 Total assets acquired $ 1,734,541 Liabilities: Deposits $ 1,321,970 Corporate debentures 9,000 Accrued interest payable 1,015 Other liabilities 13,080 Total liabilities assumed $ 1,345,065

Interest Rate Swap Derivatives

Interest Rate Swap Derivatives (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Summary Information about the Derivative Instruments	Summary information about the derivative instruments is as follows: 2018 2017 Notional amount $ 5,743,283 $ 3,740,430 Weighted average pay rate on interest-rate swaps 3.64 % 3.00 % Weighted average receive rate on interest rate swaps 3.64 % 3.00 % Weighted average maturity (years) 11 11 Fair value of interest rate swap derivatives (asset) 92,475 42,480 Fair value of interest rate swap derivatives (liability) 92,892 43,259

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018USD ($)CommunityBankClientSegments	Dec. 31, 2017USD ($)	Dec. 31, 2014Bank	Dec. 31, 2012Bank	Dec. 31, 2010Bank
Financing Receivable Allowance For Credit Losses [Line Items]
Number of community bank clients | CommunityBankClient	600
Interest bearing deposits in other financial institutions, Maximum maturity period	1 year
Loans maximum value to be monitored by payment history for non-accrual status	$ 500,000
Loans minimum value of commercial, land, development and construction loans to be monitored for non-accrual status	$ 500,000
Non real estate consumer loans typically charged off	120 days
Loans individually evaluated for impairment	$ 15,700,000	$ 20,345,000
Number of loan portfolio segments | Segments	5
Number of failed banks acquired | Bank				2	3
Tax benefit likelihood percentage	50.00%
Retained Earnings [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Reclassification of the disproportionate tax effect on unrealized losses on available for sale securities resulting from the change in federal tax rate		1,241,000
Accumulated Other Comprehensive Income (Loss) [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Reclassification of the disproportionate tax effect on unrealized losses on available for sale securities resulting from the change in federal tax rate		$ (1,241,000)
ASU No. 2016-02 [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Right-of-use lease assets	$ 21,000,000
Operating lease liabilities	$ 24,000,000
Core Deposits [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Useful life of intangible assets	10 years
Buildings [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Useful life of assets	39 years
Gulfstream Bancshares, Inc. [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Number of loan portfolio segments | Segments	5
First Southern Bancorp, Inc. [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Number of failed banks acquired | Bank			2
Minimum [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans individually evaluated for impairment	$ 500,000
Majority loans terms	3 years
Useful life of intangible assets	3 years
Range of discount rates					1.21%
Minimum [Member] | Furniture, Fixtures and Equipment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Useful life of assets	3 years
Maximum [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Majority loans terms	5 years
Useful life of intangible assets	5 years
Range of discount rates					4.53%
Maximum [Member] | Furniture, Fixtures and Equipment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Useful life of assets	15 years

Trading Securities - Trading Se

Trading Securities - Trading Securities Portfolio Realized and Unrealized Gains and Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments Debt And Equity Securities [Abstract]
Beginning balance	$ 6,777	$ 12,383
Purchases	254,555	230,074	$ 186,150
Proceeds from sales	(259,652)	(235,922)	(176,393)
Net realized gain on sales	20	195
Mark-to- market adjustment	37	47
Ending balance	$ 1,737	$ 6,777	$ 12,383

Investment Debt Securities Avai

Investment Debt Securities Available for Sale - Fair Value of Available for Sale Securities and Related Gross Unrealized Gains and Losses Recognized in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,757,380	$ 1,069,526
Gross Unrealized Gains	4,659	1,815
Gross Unrealized Losses	34,691	11,198
Fair Value	1,727,348	1,060,143
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,623,906	982,565
Gross Unrealized Gains	3,792	752
Gross Unrealized Losses	33,423	10,706
Fair Value	1,594,275	972,611
Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	88,415	71,961
Gross Unrealized Gains	698	863
Gross Unrealized Losses	335	66
Fair Value	88,778	72,758
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		5,000
Gross Unrealized Gains		200
Gross Unrealized Losses		0
Fair Value		5,200
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,265
Gross Unrealized Gains	162
Gross Unrealized Losses	0
Fair Value	6,427
Obligations of U.S. Government Sponsored Entities and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	38,794	10,000
Gross Unrealized Gains	7	0
Gross Unrealized Losses	933	426
Fair Value	$ 37,868	$ 9,574

Investment Debt Securities Av_2

Investment Debt Securities Available for Sale - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018USD ($)Security	Dec. 31, 2017USD ($)Security	Dec. 31, 2016USD ($)
Schedule of Available-for-sale Securities [Line Items]
Tax provisions related to net realized gains	$ (6,000)	$ (3,000)	$ 5,000
Securities estimated fair value	$ 961,721,000	$ 255,788,000
Debt Securities, Held-to-maturity, Restricted [Extensible List]	us-gaap:CollateralPledgedMember	us-gaap:CollateralPledgedMember
Number of securities representing specified criteria | Security	0	0
Percentage of AFS securities held by any one issuer as a percentage of shareholders' equity	10.00%	10.00%
Percentage of mortgage-backed securities held from U.S. government-sponsored entities and agencies	100.00%
Sunshine Bancorp, Inc. [Member]
Schedule of Available-for-sale Securities [Line Items]
Gain (loss) on sale of securities acquired through acquisition	$ 0
HCBF Holding Company, Inc. [Member]
Schedule of Available-for-sale Securities [Line Items]
Gain (loss) on sale of securities acquired through acquisition	$ 0

Investment Debt Securities Av_3

Investment Debt Securities Available for Sale - Schedule of Sales of Available for Sale Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments Debt And Equity Securities [Abstract]
Proceeds	$ 355,652	$ 312,692	$ 142,075
Gross gains	68	740	13
Gross losses	$ 90	$ 747	$ 0

Investment Debt Securities Av_4

Investment Debt Securities Available for Sale - Fair Value and Amortized Cost of Investment Securities by Contractual Maturity (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Investments Debt And Equity Securities [Abstract]
Available for sale, Due in one year or less, Amortized Cost	$ 966
Available for sale, Due after one year through five years, Amortized Cost	6,038
Available for sale, Due after five years through ten years, Amortized Cost	31,396
Available for sale, Due after ten years through thirty years, Amortized Cost	95,074
Available for sale, Mortgage backed securities, Amortized Cost	1,623,906
Amortized Cost	1,757,380
Investment securities available for sale, Due in one year or less, Fair Value	967
Investment securities available for sale, Due after one year through five years, Fair Value	6,080
Investment securities available for sale, Due after five years through ten years, Fair Value	30,997
Investment securities available for sale, Due after ten years through thirty years, Fair Value	95,029
Investment securities available for sale, Mortgage backed securities, Fair Value	1,594,275
Fair value	$ 1,727,348

Investment Debt Securities Av_5

Investment Debt Securities Available for Sale - Investments Gross Unrealized Losses and Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 698,058	$ 489,623
Less than 12 months, Unrealized Losses	11,430	3,364
12 months or more, Fair Value	647,951	325,640
12 months or more, Unrealized Losses	23,261	7,834
Total, Fair Value	1,346,009	815,263
Total, Unrealized Losses	34,691	11,198
Obligations of U.S. Government Sponsored Entities and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	25,104
Less than 12 months, Unrealized Losses	332
12 months or more, Fair Value	9,398	9,574
12 months or more, Unrealized Losses	601	426
Total, Fair Value	34,502	9,574
Total, Unrealized Losses	933	426
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	647,923	477,925
Less than 12 months, Unrealized Losses	10,782	3,298
12 months or more, Fair Value	635,172	316,066
12 months or more, Unrealized Losses	22,641	7,408
Total, Fair Value	1,283,095	793,991
Total, Unrealized Losses	33,423	10,706
Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	25,031	11,698
Less than 12 months, Unrealized Losses	316	66
12 months or more, Fair Value	3,381	0
12 months or more, Unrealized Losses	19	0
Total, Fair Value	28,412	11,698
Total, Unrealized Losses	$ 335	$ 66

Investment Debt Securities Held

Investment Debt Securities Held to Maturity - Fair Value of Held to Maturity Securities and Related Gross Unrecognized Gains and Losses (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 216,833	$ 232,399
Gross Unrecognized Gains	799	1,781
Gross Unrecognized Losses	5,453	2,565
Held-to-maturity securities, fair value	212,179	231,615
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	84,983	100,039
Gross Unrecognized Gains	0	0
Gross Unrecognized Losses	2,462	1,068
Held-to-maturity securities, fair value	82,521	98,971
Municipal Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	131,850	132,360
Gross Unrecognized Gains	799	1,781
Gross Unrecognized Losses	2,991	1,497
Held-to-maturity securities, fair value	$ 129,658	$ 132,644

Investment Debt Securities He_2

Investment Debt Securities Held to Maturity - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)Security	Dec. 31, 2017USD ($)Security
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity securities pledged, carrying amount | $	$ 103,710	$ 97,389
Debt securities, available-for-sale, restriction type [extensible list]	us-gaap:CollateralPledgedMember	us-gaap:CollateralPledgedMember
Number of securities representing specified criteria	0	0
Percentage of HTM securities held by any one issuer as a percentage of shareholders' equity	10.00%	10.00%
Percentage of mortgage-backed securities held from U.S. government-sponsored entities and agencies	100.00%
Held-to-maturity Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Number of securities representing specified criteria	0	0
Percentage of mortgage-backed securities held from U.S. government-sponsored entities and agencies	100.00%

Investment Debt Securities He_3

Investment Debt Securities Held to Maturity - Fair Value and Amortized Cost of Investment Securities by Contractual Maturity (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Investments Debt And Equity Securities [Abstract]
Held-to-maturity, Due after five years through ten years, Fair Value	$ 2,051
Held-to-maturity, Due after ten years through thirty years, Fair Value	127,607
Held-to-maturity, Mortgage backed securities, Fair Value	82,521
Held-to- maturity, Fair Value	212,179
Held-to-maturity, Due after five years through ten years, Amortized Cost	2,045
Held-to-maturity, Due after ten years through thirty years, Amortized Cost	129,805
Held-to-maturity, Mortgage backed securities, Amortized Cost	84,983
Held-to-maturity, Amortized Cost	$ 216,833

Investment Debt Securities He_4

Investment Debt Securities Held to Maturity - Investments Gross Unrecognized Losses and Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, Fair Value	$ 22,560	$ 70,616
Less than 12 months, Unrecognized Losses	203	637
12 months or more, Fair Value	130,328	79,668
12 months or more, Unrecognized Losses	5,250	1,928
Total, Fair Value	152,888	150,284
Total, Unrecognized Losses	5,453	2,565
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, Fair Value		57,266
Less than 12 months, Unrecognized Losses		451
12 months or more, Fair Value	82,521	41,705
12 months or more, Unrecognized Losses	2,462	617
Total, Fair Value	82,521	98,971
Total, Unrecognized Losses	2,462	1,068
Municipal Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, Fair Value	22,560	13,350
Less than 12 months, Unrecognized Losses	203	186
12 months or more, Fair Value	47,807	37,963
12 months or more, Unrecognized Losses	2,788	1,311
Total, Fair Value	70,367	51,313
Total, Unrecognized Losses	$ 2,991	$ 1,497

Loans Held for Sale - Additiona

Loans Held for Sale - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans Receivable Held For Sale Net [Line Items]
Net gains from changes in estimated fair value of mortgage loans held for sale	$ 1,081,000
Total unpaid principal balance of loans held for sale	39,318,000
Loans held for sale, past due	0
Loans held for sale, on non-accrual	0
Change in fair value	1,081,000
Net realized gain on sales	10,803,000	$ 1,511,000	$ 833,000
Mortgage Banking Derivatives [Member]
Loans Receivable Held For Sale Net [Line Items]
Net unrealized gain on mortgage banking derivatives	$ 614,000

Loans Held for Sale - Summary o

Loans Held for Sale - Summary of Activity in Mortgage Loans Held for Sale (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans Receivable Held For Sale Net [Abstract]
Beginning balance	$ 19,647	$ 2,285
Effect from acquisitions	8,959
Loans originated	403,492	93,642	$ 39,748
Proceeds from sales	(403,583)	(77,791)	(40,557)
Change in fair value	1,081
Net realized gain on sales	10,803	1,511	833
Ending balance	$ 40,399	$ 19,647	$ 2,285

Loans Held for Sale - Schedule

Loans Held for Sale - Schedule of Summarizes The Notional Amounts For Interest Rate Lock Commitments And Best Efforts Forward Trades and MBS Forward Trades Pertaining To Loans Held For Sale (Detail) - Loans Held for Sale [Member] $ in Thousands	Dec. 31, 2018USD ($)
Loans Held For Sale [Line Items]
Total derivative instruments	$ 141,410
Interest Rate Lock Commitments [Member]
Loans Held For Sale [Line Items]
Total derivative instruments	49,545
Best Efforts Forward Trades [Member]
Loans Held For Sale [Line Items]
Total derivative instruments	61,865
MBS Forward Trades [Member]
Loans Held For Sale [Line Items]
Total derivative instruments	$ 30,000

Loans - Summary of Information

Loans - Summary of Information Concerning Loan Portfolio by Collateral Types (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Receivables with Imputed Interest [Line Items]
Total loans excluding purchased credit impaired loans	$ 8,181,533	$ 4,609,063
Total PCI loans	158,971	164,158
Total loans	8,340,504	4,773,221
Allowance for loan losses for loans that are not PCI loans	(39,579)	(32,530)
Net Loans	8,300,734	4,740,396
Allowance for loan losses for loans that are not PCI loans [Member]
Receivables with Imputed Interest [Line Items]
Real estate loans, Residential	1,702,114	1,025,303
Real estate loans, Commercial	4,454,098	2,546,143
Land, development and construction	635,562	235,816
Total real estate	6,791,774	3,807,262
Commercial	1,183,380	693,501
Consumer and other loans	203,686	107,480
Loans before unearned fees and deferred cost	8,178,840	4,608,243
Net unearned fees and costs	2,693	820
Allowance for loan losses on PCI loans [Member]
Receivables with Imputed Interest [Line Items]
Real estate loans, Residential	58,804	59,975
Real estate loans, Commercial	87,336	92,791
Land, development and construction	7,028	6,656
Total real estate	153,168	159,422
Commercial	5,594	4,444
Consumer and other loans	209	292
Allowance for loan losses for PCI loans	$ (191)	$ (295)

Loans - Summary of Allowance fo

Loans - Summary of Allowance for Loan Losses and Recorded Investment in Loans by Portfolios (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	$ 32,825
Provision for loan losses	8,283	$ 4,958	$ 4,962
Balance at end of period	39,770	32,825
Allowance for loan losses for loans that are not PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	32,530	26,569	22,143
Charge-offs	(3,835)	(1,999)	(2,747)
Recoveries	2,432	2,759	2,628
Provision for loan losses	8,452	5,201	4,545
Balance at end of period	39,579	32,530	26,569
Allowance for loan losses on PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	295	472	121
Charge-offs	(10)		(66)
Recoveries	75	66
Provision for loan losses	(169)	(243)	417
Balance at end of period	191	295	472
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	6,003
Balance at end of period	5,518	6,003
Residential Real Estate [Member] | Allowance for loan losses for loans that are not PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	6,003	5,640	6,015
Charge-offs	(516)	(254)	(290)
Recoveries	1,027	950	1,220
Provision for loan losses	(996)	(333)	(1,305)
Balance at end of period	5,518	6,003	5,640
Residential Real Estate [Member] | Allowance for loan losses on PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period		54
Provision for loan losses		(54)	54
Balance at end of period			54
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	19,363
Balance at end of period	22,978	19,363
Commercial Real Estate [Member] | Allowance for loan losses for loans that are not PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	19,304	14,713	10,559
Charge-offs	(13)	(74)	(1,190)
Recoveries	679	662	625
Provision for loan losses	3,008	4,003	4,719
Balance at end of period	22,978	19,304	14,713
Commercial Real Estate [Member] | Allowance for loan losses on PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	59	92	103
Recoveries		66
Provision for loan losses	(59)	(99)	(11)
Balance at end of period		59	92
Land, Development, Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	1,401
Balance at end of period	1,958	1,401
Land, Development, Construction [Member] | Allowance for loan losses for loans that are not PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	1,179	883	936
Charge-offs	(126)		(232)
Recoveries	39	596	269
Provision for loan losses	689	(300)	(90)
Balance at end of period	1,781	1,179	883
Land, Development, Construction [Member] | Allowance for loan losses on PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	222	312	1
Charge-offs			(66)
Provision for loan losses	(45)	(90)	377
Balance at end of period	177	222	312
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	4,130
Balance at end of period	6,414	4,130
Commercial and Industrial [Member] | Allowance for loan losses for loans that are not PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	4,130	3,785	3,212
Charge-offs	(1,474)	(677)	(186)
Recoveries	360	334	325
Provision for loan losses	3,398	688	434
Balance at end of period	6,414	4,130	3,785
Commercial and Industrial [Member] | Allowance for loan losses on PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period			3
Charge-offs	(10)
Recoveries	75
Provision for loan losses	(65)		(3)
Consumer and Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	1,928
Balance at end of period	2,902	1,928
Consumer and Other [Member] | Allowance for loan losses for loans that are not PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	1,914	1,548	1,421
Charge-offs	(1,706)	(994)	(849)
Recoveries	327	217	189
Provision for loan losses	2,353	1,143	787
Balance at end of period	2,888	1,914	1,548
Consumer and Other [Member] | Allowance for loan losses on PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning of the period	14	14	14
Balance at end of period	$ 14	$ 14	$ 14

Loans - Allowance for Loan Loss

Loans - Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Allowance for loan losses:
Individually evaluated for impairment	$ 1,616	$ 804
Collectively evaluated for impairment	37,963	31,726
Purchased credit-impaired	191	295
Total ending allowance balance	39,770	32,825
Loans:
Individually evaluated for impairment	15,700	20,345
Collectively evaluated for impairment	8,163,140	4,587,898
Purchased credit-impaired	158,971	164,158
Total ending loan balances	8,337,811	4,772,401
Residential Real Estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	331	586
Collectively evaluated for impairment	5,187	5,417
Total ending allowance balance	5,518	6,003
Loans:
Individually evaluated for impairment	6,234	8,101
Collectively evaluated for impairment	1,695,880	1,017,202
Purchased credit-impaired	58,804	59,975
Total ending loan balances	1,760,918	1,085,278
Commercial Real Estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	250
Collectively evaluated for impairment	22,728	19,304
Purchased credit-impaired		59
Total ending allowance balance	22,978	19,363
Loans:
Individually evaluated for impairment	7,496	8,218
Collectively evaluated for impairment	4,446,602	2,537,925
Purchased credit-impaired	87,336	92,791
Total ending loan balances	4,541,434	2,638,934
Land, Development, Construction [Member]
Allowance for loan losses:
Individually evaluated for impairment		4
Collectively evaluated for impairment	1,781	1,175
Purchased credit-impaired	177	222
Total ending allowance balance	1,958	1,401
Loans:
Individually evaluated for impairment	117	331
Collectively evaluated for impairment	635,445	235,485
Purchased credit-impaired	7,028	6,656
Total ending loan balances	642,590	242,472
Commercial and Industrial [Member]
Allowance for loan losses:
Individually evaluated for impairment	1,034	206
Collectively evaluated for impairment	5,380	3,924
Total ending allowance balance	6,414	4,130
Loans:
Individually evaluated for impairment	1,708	3,497
Collectively evaluated for impairment	1,181,672	690,004
Purchased credit-impaired	5,594	4,444
Total ending loan balances	1,188,974	697,945
Consumer and Other [Member]
Allowance for loan losses:
Individually evaluated for impairment	1	8
Collectively evaluated for impairment	2,887	1,906
Purchased credit-impaired	14	14
Total ending allowance balance	2,902	1,928
Loans:
Individually evaluated for impairment	145	198
Collectively evaluated for impairment	203,541	107,282
Purchased credit-impaired	209	292
Total ending loan balances	$ 203,895	$ 107,772

Loans - Summary of Impaired Loa

Loans - Summary of Impaired Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Mortgage Loans On Real Estate [Line Items]
Total TDRs (these are included in impaired loans)	$ 9,477	$ 12,779
Impaired loans that are not TDRs	6,223	7,566
Total impaired loans	15,700	20,345
Performing TDRs [Member]
Mortgage Loans On Real Estate [Line Items]
Total TDRs (these are included in impaired loans)	8,475	12,081
Non-performing TDRs [Member]
Mortgage Loans On Real Estate [Line Items]
Total TDRs (these are included in impaired loans)	$ 1,002	$ 698

Loans - Additional Information

Loans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans [Line Items]
Loans modification, modified terms allowance period minimum	12 years
Loans modification, modified terms allowance period maximum	24 months
Troubled debt restructured loans total	$ 9,477,000
Performing TDRs (these are not included in nonperforming loans ("NPLs"))	8,475,000
Non-performing TDRs	1,002,000
Provision for loan loss expense	77,000	$ 265,000	$ 454,000
Partial charge offs for troubled debt restructured	$ 44,000	72,000	209,000
Percentage of troubled debt restructured current pursuant to modified terms	89.00%
Percentage of troubled debt restructured not performing pursuant to their modified terms	11.00%
Loans modified as TDRs	$ 1,830,000	2,258,000	4,079,000
Loan loss provision modified as TDRs	9,000	14,000	229,000
Provision for loan loss expense within twelve months	0	8,000	76,000
Partial charge offs for troubled debt restructured	0	8,000	77,000
Loan receivable modification, Specific reserve for customers	334,000	601,000
Allowances for loan losses	8,283,000	4,958,000	4,962,000
Reclassification from non-accretable difference	22,469,000	4,707,000	6,220,000
Income accretion	35,944,000
Allowance for loan losses on PCI loans [Member]
Loans [Line Items]
Allowances for loan losses	$ (169,000)	$ (243,000)	$ 417,000

Loans - Troubled Debt Restructu

Loans - Troubled Debt Restructured Loans by Loans Type (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
TDRs	$ 9,477	$ 12,779
Total Real Estate Loans [Member]
Financing Receivable, Modifications [Line Items]
TDRs	8,755	12,025
Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	8,475	12,081
Accruing [Member] | Total Real Estate Loans [Member]
Financing Receivable, Modifications [Line Items]
TDRs	7,762	11,355
Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs	1,002	698
Non Accrual [Member] | Total Real Estate Loans [Member]
Financing Receivable, Modifications [Line Items]
TDRs	993	670
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
TDRs	6,234	8,101
Residential Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	5,848	7,737
Residential Real Estate [Member] | Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs	386	364
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
TDRs	2,403	3,592
Commercial Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	1,837	3,286
Commercial Real Estate [Member] | Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs	566	306
Land, Development, Construction [Member]
Financing Receivable, Modifications [Line Items]
TDRs	118	332
Land, Development, Construction [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	77	332
Land, Development, Construction [Member] | Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs	41
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
TDRs	577	556
Commercial and Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	577	556
Consumer and Other [Member]
Financing Receivable, Modifications [Line Items]
TDRs	145	198
Consumer and Other [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	136	170
Consumer and Other [Member] | Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs	$ 9	$ 28

Loans - Summary of Loans by Cla

Loans - Summary of Loans by Class Modified (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)SecurityLoan	Dec. 31, 2017USD ($)SecurityLoan	Dec. 31, 2016USD ($)SecurityLoan
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan	2	1	4
Recorded investment | $	$ 482	$ 177	$ 1,103
Residential Real Estate [Member]
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan			2
Recorded investment | $			$ 167
Commercial Real Estate [Member]
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan	1	1	2
Recorded investment | $	$ 433	$ 177	$ 936
Land, Development, Construction [Member]
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan	1
Recorded investment | $	$ 49

Loans - Summary of Loans Indivi

Loans - Summary of Loans Individually Evaluated for Impairment by Class of Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	$ 16,593	$ 21,869
Total impaired loans	15,700	20,345
Amount of allowance for loan losses allocated to impaired loans	1,616	804
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	3,608	4,945
Unpaid principal balance, With an allowance recorded	2,897	3,426
Recorded investment, With no related allowance	3,485	4,818
Recorded investment, With an allowance recorded	2,749	3,283
Total impaired loans	6,234	8,101
Amount of allowance for loan losses allocated to impaired loans	331	586
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	6,447	8,973
Unpaid principal balance, With an allowance recorded	1,593
Recorded investment, With no related allowance	5,906	8,218
Recorded investment, With an allowance recorded	1,590
Total impaired loans	7,496	8,218
Amount of allowance for loan losses allocated to impaired loans	250
Land, Development, Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	144	260
Unpaid principal balance, With an allowance recorded		140
Recorded investment, With no related allowance	117	210
Recorded investment, With an allowance recorded		121
Total impaired loans	117	331
Amount of allowance for loan losses allocated to impaired loans		4
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	364	3,374
Unpaid principal balance, With an allowance recorded	1,378	531
Recorded investment, With no related allowance	353	2,968
Recorded investment, With an allowance recorded	1,355	529
Total impaired loans	1,708	3,497
Amount of allowance for loan losses allocated to impaired loans	1,034	206
Consumer and Other [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	109	142
Unpaid principal balance, With an allowance recorded	53	78
Recorded investment, With no related allowance	108	127
Recorded investment, With an allowance recorded	37	71
Total impaired loans	145	198
Amount of allowance for loan losses allocated to impaired loans	$ 1	$ 8

Loans - Summary of Impairment b

Loans - Summary of Impairment by Class of Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	$ 18,211	$ 19,327	$ 23,644
Interest income recognized during impairment	461	469	467
Total Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	15,956	17,119	21,583
Interest income recognized during impairment	420	430	412
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	7,492	7,731	8,384
Interest income recognized during impairment	308	267	257
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	7,876	8,956	11,696
Interest income recognized during impairment	104	145	131
Land, Development, Construction [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	588	432	1,503
Interest income recognized during impairment	8	18	24
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	2,081	1,968	1,808
Interest income recognized during impairment	33	29	44
Consumer and Other [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	174	240	253
Interest income recognized during impairment	$ 8	$ 10	$ 11

Loans - Summary of Recorded Inv

Loans - Summary of Recorded Investment in Non-accrual Loans and Loans Past Due Over 90 Days Still on Accrual by Class of Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	$ 23,567	$ 17,288
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	11,488	7,107
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	8,445	6,549
Land, Development, Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	795	138
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	2,274	3,121
Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	$ 565	$ 373

Loans - Summary Aging of Record

Loans - Summary Aging of Recorded Investment in Past Due Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 8,178,840	$ 4,608,243
Total Past Due	36,502	13,665
Loans Not Past Due	8,118,771	4,577,290
Non-accrual loans	23,567	17,288
30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	21,094	8,572
60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	15,408	5,093
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	1,702,114	1,025,303
Total Past Due	11,360	5,389
Loans Not Past Due	1,679,266	1,012,807
Non-accrual loans	11,488	7,107
Residential Real Estate [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,730	3,568
Residential Real Estate [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,631	1,821
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	4,454,098	2,546,143
Total Past Due	15,446	3,430
Loans Not Past Due	4,430,207	2,536,164
Non-accrual loans	8,445	6,549
Commercial Real Estate [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10,840	1,158
Commercial Real Estate [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,607	2,272
Land, Development, Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	635,562	235,816
Total Past Due	4,683	2,996
Loans Not Past Due	630,084	232,682
Non-accrual loans	795	138
Land, Development, Construction [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	661	2,807
Land, Development, Construction [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,022	189
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	1,183,380	693,501
Total Past Due	3,681	1,331
Loans Not Past Due	1,177,425	689,049
Non-accrual loans	2,274	3,121
Commercial and Industrial [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,803	568
Commercial and Industrial [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	878	763
Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	203,686	107,480
Total Past Due	1,332	519
Loans Not Past Due	201,789	106,588
Non-accrual loans	565	373
Consumer and Other [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,061	471
Consumer and Other [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 271	$ 48

Loans - Risk Category of Loans

Loans - Risk Category of Loans by Class of Loans, Excluding Purchased Credit Impaired Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 1,702,114	$ 1,025,303
Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	203,686	107,480
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	7,831,100	4,397,611
Pass [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,633,810	987,472
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,246,687	2,411,085
Pass [Member] | Land, Development, Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	610,631	217,555
Pass [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,137,272	674,764
Pass [Member] | Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	202,701	106,735
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	264,172	168,401
Special Mention [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	41,522	20,435
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	160,981	115,942
Special Mention [Member] | Land, Development, Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	20,586	17,699
Special Mention [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	40,836	14,186
Special Mention [Member] | Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	247	139
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	83,568	42,231
Substandard [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	26,782	17,396
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	46,430	19,116
Substandard [Member] | Land, Development, Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,345	562
Substandard [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	5,272	4,551
Substandard [Member] | Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 738	$ 606

Loans - Investment in Residenti

Loans - Investment in Residential and Consumer Loans, Excluding Loans from Purchased Credit Impaired Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 1,702,114	$ 1,025,303
Residential Real Estate [Member] | Performing TDRs [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,690,626	1,018,196
Residential Real Estate [Member] | Non-performing TDRs [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	11,488	7,107
Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	203,686	107,480
Consumer and Other [Member] | Performing TDRs [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	203,121	107,107
Consumer and Other [Member] | Non-performing TDRs [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 565	$ 373

Loans - Summary of Total Contra

Loans - Summary of Total Contractually Required Principal and Interest Cash Payments, Management's Estimate of Expected Total Cash Payments and Carrying Value of Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Contractually required principal and interest	$ 267,815	$ 248,283	$ 297,821
Non-accretable difference	(38,602)	(13,183)	(18,372)
Cash flows expected to be collected	229,213	235,100	279,449
Accretable yield	(70,242)	(70,942)	(93,525)
Carrying value of acquired loans	158,971	164,158	185,924
Allowance for loan losses	(191)	(295)	(472)
Carrying value less allowance for loan losses	$ 158,780	$ 163,863	$ 185,452

Loans - Summary of Changes in T

Loans - Summary of Changes in Total Contractually Required Principal and Interest Cash Payments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Contractually required principal and interest, beginning balance	$ 248,283	$ 297,821
Non-accretable difference, beginning balance	(13,183)	(18,372)
Cash flows expected to be collected, beginning balance	235,100	279,449
Accretable yield, beginning balance	(70,942)	(93,525)
Carrying value of acquired loans, beginning balance	164,158	185,924
Income accretion	35,944
Contractually required principal and interest, ending balance	267,815	248,283	$ 297,821
Non-accretable difference, ending balance	(38,602)	(13,183)	(18,372)
Cash flows expected to be collected, ending balance	229,213	235,100	279,449
Accretable yield, ending balance	(70,242)	(70,942)	(93,525)
Carrying value of acquired loans, ending balance	158,971	164,158	185,924
Contractually Required Principal and Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Contractually required principal and interest, beginning balance	248,283	297,821	332,570
Effect of acquisitions	122,392	31,334	73,005
All other adjustments	(102,860)	(80,872)	(107,754)
Contractually required principal and interest, ending balance	267,815	248,283	297,821
Non-Accretable Difference [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-accretable difference, beginning balance	(13,183)	(18,372)	(19,452)
Effect of acquisitions	(58,927)	(7,104)	(9,295)
All other adjustments	33,508	12,293	10,375
Non-accretable difference, ending balance	(38,602)	(13,183)	(18,372)
Cash Flows Expected to be Collected [Member]
Financing Receivable, Recorded Investment [Line Items]
Cash flows expected to be collected, beginning balance	235,100	279,449	313,118
Effect of acquisitions	63,465	24,230	63,710
All other adjustments	(69,352)	(68,579)	(97,379)
Cash flows expected to be collected, ending balance	229,213	235,100	279,449
Accretable Yield [Member]
Financing Receivable, Recorded Investment [Line Items]
Accretable yield, beginning balance	(70,942)	(93,525)	(102,590)
Effect of acquisitions	(7,770)	(4,185)	(18,585)
Income accretion	35,944	32,388	34,006
All other adjustments	(27,474)	(5,620)	(6,356)
Accretable yield, ending balance	(70,242)	(70,942)	(93,525)
Carry Value of Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Carrying value of acquired loans, beginning balance	164,158	185,924	210,528
Effect of acquisitions	55,695	20,045	45,125
Income accretion	35,944	32,388	34,006
All other adjustments	(96,826)	(74,199)	(103,735)
Carrying value of acquired loans, ending balance	$ 158,971	$ 164,158	$ 185,924

Other Real Estate Owned - Activ

Other Real Estate Owned - Activity of Valuation Allowance in Other Real Estate Owned and Expense Related to Foreclosed Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real Estate [Abstract]
Beginning of year	$ 861	$ 869	$ 1,297
Valuation write down of repossessed real estate (“OREO”)	482	682	871
Sales and/or dispositions	(939)	(690)	(1,299)
End of year	404	861	869
Expenses related to foreclosed real estate include:
Gain on sale of repossessed real estate owned	(1,933)	(876)	(1,528)
Valuation write down of repossessed real estate (“OREO”)	482	682	871
Operating expenses, net of rental income	2,815	2,252	2,392
Total	$ 1,364	$ 2,058	$ 1,735

Fair Value - Additional Informa

Fair Value - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans with allocated allowance for loan losses	$ 8,829	$ 11,673
Impaired valuation allowance	1,463	477
Provision for loan loss expense on impaired loans	8,283	4,958	$ 4,962
Repossessed real estate owned valuation write down	482	682	871
Impairment on bank property held for sale	2,667	519	$ 1,150
Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Provision for loan loss expense on impaired loans	$ 1,363	$ 842
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization rates to determine fair value of collateral	7.00%
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization rates to determine fair value of collateral	10.00%

Fair Value - Assets and Liabili

Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets:
Trading securities, at fair value	$ 1,737	$ 6,777
Available for sale debt securities	1,727,348	1,060,143
Loans held for sale, at fair value, carrying amount	40,399	19,647
Mortgage servicing assets, carrying amount	1,565
Mortgage banking derivatives, carrying amount assets	783
Interest rate swap derivatives, carrying amount assets	92,475	42,480
Liabilities:
Mortgage banking derivatives, carrying amount liability	169
Interest rate swap derivatives, carrying amount liability	92,892	43,259
Mortgage Backed Securities [Member]
Assets:
Available for sale debt securities	1,594,275	972,611
Municipal Securities [Member]
Assets:
Available for sale debt securities	88,778	72,758
U.S. Treasury Securities [Member]
Assets:
Available for sale debt securities		5,200
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Trading securities, at fair value	1,737	6,777
Available for sale debt securities	1,727,348	1,060,143
Liabilities:
Mortgage banking derivatives, carrying amount liability	164
Significant Unobservable Inputs (Level 3) [Member]
Liabilities:
Mortgage banking derivatives, carrying amount liability	5
Fair Value Measurements on Recurring [Member] | Carrying value [Member]
Assets:
Trading securities, at fair value	1,737	6,777
Loans held for sale, at fair value, carrying amount	40,399
Mortgage servicing assets, carrying amount	1,565
Mortgage banking derivatives, carrying amount assets	783
Interest rate swap derivatives, carrying amount assets	92,475	42,480
Liabilities:
Mortgage banking derivatives, carrying amount liability	169
Interest rate swap derivatives, carrying amount liability	92,892	43,259
Fair Value Measurements on Recurring [Member] | Carrying value [Member] | Corporate Debt Securities [Member]
Assets:
Available for sale debt securities	6,427
Fair Value Measurements on Recurring [Member] | Carrying value [Member] | Obligations of U.S. Government Sponsored Entities and Agencies [Member]
Assets:
Available for sale debt securities	37,868	9,574
Fair Value Measurements on Recurring [Member] | Carrying value [Member] | Mortgage Backed Securities [Member]
Assets:
Available for sale debt securities	1,594,275	972,611
Fair Value Measurements on Recurring [Member] | Carrying value [Member] | Municipal Securities [Member]
Assets:
Available for sale debt securities	88,778	72,758
Fair Value Measurements on Recurring [Member] | Carrying value [Member] | U.S. Treasury Securities [Member]
Assets:
Available for sale debt securities		5,200
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Trading securities, at fair value	1,737	6,777
Loans held for sale, at fair value, carrying amount	40,399
Mortgage servicing assets, carrying amount	1,565
Interest rate swap derivatives, carrying amount assets	92,475	42,480
Liabilities:
Mortgage banking derivatives, carrying amount liability	164
Interest rate swap derivatives, carrying amount liability	92,892	43,259
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member]
Assets:
Available for sale debt securities	6,427
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Obligations of U.S. Government Sponsored Entities and Agencies [Member]
Assets:
Available for sale debt securities	37,868	9,574
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage Backed Securities [Member]
Assets:
Available for sale debt securities	1,594,275	972,611
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Municipal Securities [Member]
Assets:
Available for sale debt securities	88,778	72,758
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury Securities [Member]
Assets:
Available for sale debt securities		$ 5,200
Fair Value Measurements on Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Mortgage banking derivatives, carrying amount assets	783
Liabilities:
Mortgage banking derivatives, carrying amount liability	$ 5

Fair Value - Assets and Liabi_2

Fair Value - Assets and Liabilities Measured at Fair Value on Non-Recurring Basis (Detail) - Fair Value Measurements on Non-Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans on Residential real estate at Carrying value	$ 1,811	$ 2,423
Impaired loans on Commercial real estate at Carrying value	5,614	6,293
Impaired loans on Land, land development and construction at Carrying value	90	292
Impaired loans on Commercial at Carrying value	1,274	2,131
Impaired loans on Consumer at Carrying value	40	57
Other real estate owned on Residential real estate at Carrying value		635
Other real estate owned on Commercial real estate at Carrying value		261
Other real estate owned on Land, land development and construction at Carrying value	867	1,481
Bank owned real estate held for sale	5,805	1,516
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank owned real estate held for sale	5,805	1,516
Impaired loans on Residential real estate	1,811	2,423
Impaired loans on Commercial real estate	5,614	6,293
Impaired loans on Land, land development and construction	90	292
Impaired loans on Commercial	1,274	2,131
Impaired loans on Consumer	40	57
Other real estate owned on Residential real estate		635
Other real estate owned on Commercial real estate		261
Other real estate owned on Land, land development and construction	$ 867	$ 1,481

Fair Value - Carrying Amounts a

Fair Value - Carrying Amounts and Estimated Fair Values of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financial assets:
Cash and cash equivalents	$ 367,333	$ 280,619
Cash and cash equivalents, fair value	367,333	280,619
Trading securities, at fair value	1,737	6,777
Available for sale debt securities, at fair value	1,727,348	1,060,143
Held to maturity debt securities, carrying amount	216,833	232,399
Held to maturity debt securities at fair value	212,179	231,615
Federal Home Loan Bank, Federal Reserve Bank and other stock, at cost	79,584	34,876
Loans held for sale, carrying value	40,399	19,647
Loans held for sale, fair value	40,399	19,647	$ 2,285
Loans, net, carrying amount	8,300,734	4,740,396
Loans, net, fair value	8,342,220	4,731,514
Mortgage servicing assets, carrying amount	1,565
Mortgage banking derivatives, carrying amount assets	783
Interest rate swap derivatives, carrying amount assets	92,475	42,480
Interest rate swap derivatives, assets fair value	92,475	42,480
Accrued interest receivable, carrying amount	33,143	18,628
Accrued interest receivable, fair value	33,143	18,628
Mortgage servicing assets, at fair value	1,565
Mortgage banking derivatives, assets fair value	783
Financial liabilities:
Deposits- without stated maturities, carrying amount	7,655,376	4,727,840
Deposits- without stated maturities, fair value	7,655,376	4,727,840
Deposits- with stated maturities, carrying amount	1,821,960	832,683
Deposits- with stated maturities, fair value	1,827,299	845,039
Securities sold under agreement to repurchase, fair value	57,772	52,080
Securities sold under agreement to repurchase	57,772	52,080
Federal funds purchased and other borrowings, carrying amount	655,360	331,490
Corporate debentures, carrying amount	32,415	26,192
Mortgage banking derivatives, carrying amount liability	169
Interest rate swap derivatives, carrying amount	92,892	43,259
Corporate debentures, fair value	28,621	22,363
Accrued interest payable, carrying amount	2,627	1,169
Interest rate swap derivatives, fair value	92,892	43,259
Accrued interest payable, fair value	2,627	1,169
Federal funds purchased and other borrowings, fair value	655,360	331,490
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets:
Cash and cash equivalents, fair value	367,333	280,619
Financial liabilities:
Deposits- without stated maturities, fair value	7,655,376	4,727,840
Significant Other Observable Inputs (Level 2) [Member]
Financial assets:
Trading securities, at fair value	1,737	6,777
Available for sale debt securities, at fair value	1,727,348	1,060,143
Held to maturity debt securities at fair value	212,179	231,615
Loans held for sale, fair value	40,399	19,647
Interest rate swap derivatives, assets fair value	92,475	42,480
Accrued interest receivable, fair value	8,355	5,370
Mortgage servicing assets, at fair value	1,565
Financial liabilities:
Deposits- with stated maturities, fair value	1,827,299	845,039
Securities sold under agreement to repurchase, fair value	57,772	52,080
Mortgage banking derivatives, carrying amount liability	164
Interest rate swap derivatives, fair value	92,892	43,259
Accrued interest payable, fair value	2,627	1,169
Federal funds purchased and other borrowings, fair value	655,360	331,490
Significant Unobservable Inputs (Level 3) [Member]
Financial assets:
Loans, net, fair value	8,342,220	4,731,514
Accrued interest receivable, fair value	24,788	13,258
Mortgage banking derivatives, assets fair value	783
Financial liabilities:
Mortgage banking derivatives, carrying amount liability	5
Corporate debentures, fair value	$ 28,621	$ 22,363

Bank Premises and Equipment - S

Bank Premises and Equipment - Summary of Bank Premises and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Bank premises and equipment, Gross	$ 278,494	$ 188,620
Less: Accumulated depreciation	51,040	46,734
Bank premises and equipment, Net	227,454	141,886
Land [Member]
Property, Plant and Equipment [Line Items]
Bank premises and equipment, Gross	72,487	51,724
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Bank premises and equipment, Gross	1,381	1,251
Buildings [Member]
Property, Plant and Equipment [Line Items]
Bank premises and equipment, Gross	130,424	85,625
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Bank premises and equipment, Gross	13,655	6,575
Furniture, Fixtures and Equipment [Member]
Property, Plant and Equipment [Line Items]
Bank premises and equipment, Gross	45,056	38,662
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Bank premises and equipment, Gross	$ 15,491	$ 4,783

Bank Premises and Equipment - M

Bank Premises and Equipment - Minimum Future Contractual Annual Rentals (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Property Plant And Equipment [Abstract]
2,018	$ 7,113
2,019	5,687
2,020	5,004
2,021	4,274
2,022	3,163
Thereafter	15,047
Total	$ 40,288

Bank Premises and Equipment - A

Bank Premises and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Rental expense, net	$ 5,642	$ 2,996	$ 1,955
Annual rental income	$ 1,183	$ 930	$ 892

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Change in Balance for Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning of year	$ 257,683	$ 106,028	$ 76,739
Acquired goodwill	545,197	151,655	29,289
Impairment	0	0	0
End of year	$ 802,880	$ 257,683	$ 106,028

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Additional Information (Detail)	Sep. 01, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Finite Lived Intangible Assets [Line Items]
Amortized period on accelerated basis		10 years
Acquired total servicing assets	$ 1,828,000
Impairment charges	0
Servicing assets fair value		$ 1,388,000	$ 551,000	$ 85,000
SBA [Member]
Finite Lived Intangible Assets [Line Items]
Impairment charges	$ 0
Loans serviced for others		226,000,000
Loans sold with servicing assets retained		35,779,000,000	26,315,000,000
Amortization of servicing assets		235,000	69,000
Servicing assets fair value		$ 1,388,000	$ 551,000
Minimum [Member] | Discount Rate [Member]
Finite Lived Intangible Assets [Line Items]
Servicing asset input rate		0.004
Minimum [Member] | Prepayment Speed Rate [Member]
Finite Lived Intangible Assets [Line Items]
Servicing asset input rate		0.066
Minimum [Member] | Weighted Average Default Rate [Member]
Finite Lived Intangible Assets [Line Items]
Servicing asset input rate		0.005
Maximum [Member] | Discount Rate [Member]
Finite Lived Intangible Assets [Line Items]
Servicing asset input rate		0.011
Maximum [Member] | Prepayment Speed Rate [Member]
Finite Lived Intangible Assets [Line Items]
Servicing asset input rate		0.155
Maximum [Member] | Weighted Average Default Rate [Member]
Finite Lived Intangible Assets [Line Items]
Servicing asset input rate		0.005

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Acquired Intangible Assets for Core Deposit Intangibles and Trust Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Beginning of year	$ 24,063	$ 16,209	$ 13,001
Disposal of Trust intangible asset	0	(573)	0
End of year	66,225	24,063	16,209
Core Deposits [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired	51,945	12,424	6,282
Core Deposits Intangible And Trust Intangible [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ (9,783)	$ (3,997)	$ (3,074)

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Schedule of Core Deposit Intangibles and Trust Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized intangible assets:
Accumulated Amortization	$ 27,739	$ 17,956
Gross Carrying Amount	93,964	42,019
Core Deposit Intangibles [Member]
Amortized intangible assets:
Accumulated Amortization	27,739	17,956
Gross Carrying Amount	$ 93,964	$ 42,019

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets - Estimated Amortization Expense (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2,019	$ 10,479
2,020	9,111
2,021	7,923
2,022	7,245
2,023	$ 7,165

Goodwill and Intangible Asset_7

Goodwill and Intangible Assets - Schedule of Activity for MSA and the Related Valuation Allowance (Detail) - Mortgage Servicing Asset [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Finite Lived Intangible Assets [Line Items]
Effect from acquisitions	$ 1,602
Changes in fair value	(37)
End of year	$ 1,565

Goodwill and Intangible Asset_8

Goodwill and Intangible Assets - Schedule of Activity for SBA Servicing Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning of year	$ 551	$ 85
Additions	846	535
Effect from acquisitions	226
Amortized to expense	(235)	(69)
End of year	$ 1,388	$ 551

Deposits - Summary of Deposits

Deposits - Summary of Deposits (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Banking And Thrift [Abstract]
Non-interest bearing deposits	$ 2,923,640	$ 1,999,901
Interest bearing deposits:
Interest bearing demand deposits	1,811,006	1,058,985
Savings deposits	704,159	501,014
Money market accounts	2,216,571	1,167,940
Time deposits less than $100,000	871,043	384,347
Time deposits of $100,000 or greater	950,917	448,336
Total deposits	$ 9,477,336	$ 5,560,523
Interest bearing demand deposits, Weighted Average Interest Rate	0.30%	0.10%
Savings deposits, Weighted Average Interest Rate	0.10%	0.10%
Money market accounts, Weighted Average Interest Rate	0.90%	0.40%
Time deposits less than $100, Weighted Average Interest Rate	1.60%	1.00%
Time deposits of $100 or greater, Weighted Average Interest Rate	1.60%	1.20%
Total deposits, Weighted Average Interest Rate	0.60%	0.30%

Deposits - Summary of Certifica

Deposits - Summary of Certificate Accounts (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Banking And Thrift [Abstract]
2,019	$ 1,337,688
2,020	320,487
2,021	89,880
2,022	39,552
2,023	33,965
Thereafter	388
Total	$ 1,821,960	$ 832,683

Deposits - Additional Informati

Deposits - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Brokered Deposits	$ 328,718	$ 222,368
FDIC [Member]
Summary Of Investments Other Than Investments In Related Parties Reportable Data [Line Items]
Time deposits of $250 thousands or greater	$ 397,369	$ 197,247

Securities Sold Under Agreeme_3

Securities Sold Under Agreements to Repurchase - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Banking And Thrift [Abstract]
Securities sold under agreement to repurchase	$ 57,772	$ 52,080
Collateral pledged against repurchase agreement	$ 64,706	$ 59,682

Securities Sold Under Agreeme_4

Securities Sold Under Agreements to Repurchase - Summary of Repurchase Agreement (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets Sold Under Agreements To Repurchase [Line Items]
Market value of securities pledged	$ 64,706	$ 59,682
Securities sold under agreement to repurchase	$ 57,772	$ 52,080
Market value pledged as a % of borrowings	112.00%	115.00%
Average daily balance during the year	$ 54,344	$ 43,850	$ 29,435
Average interest rate during the year	1.16%	0.56%	0.35%
Maximum month-end balance during the year	$ 59,751	$ 52,080	$ 35,500
Weighted average interest rate at year end	1.66%	0.88%	0.33%
Mortgage Backed Securities [Member]
Assets Sold Under Agreements To Repurchase [Line Items]
Market value of securities pledged	$ 64,269	$ 59,239
Securities sold under agreement to repurchase	$ 57,594	$ 52,030
Market value pledged as a % of borrowings	112.00%	114.00%
Municipal Securities [Member]
Assets Sold Under Agreements To Repurchase [Line Items]
Market value of securities pledged	$ 437	$ 443
Securities sold under agreement to repurchase	$ 178	$ 50
Market value pledged as a % of borrowings	246.00%	886.00%

Federal Funds Purchased - Addit

Federal Funds Purchased - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Federal funds purchased	$ 294,360,000	$ 331,490,000
Overnight Borrowings / Advances [Member]
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Federal funds purchased		$ 70,000
Federal funds purchased, weighted average interest rate		1.63%

Federal Funds Purchased - Feder

Federal Funds Purchased - Federal Funds Purchased Overnight Deposits from Correspondent Banks (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Banking And Thrift [Abstract]
Average daily balance during the year	$ 250,499	$ 263,669	$ 210,276
Average interest rate during the period	2.02%	1.13%	0.55%
Maximum month-end balance during the year	$ 294,360	$ 335,531	$ 288,582
Weighted average interest rate at year end	2.07%	1.39%	0.72%

Other Borrowed Funds - Summary

Other Borrowed Funds - Summary of Advances from Federal Home Loan Bank (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Banking And Thrift [Abstract]
Fixed rate advances, maturity through 01/28/2019, rates from 2.45% and 2.54%, averaging 2.50%	$ 200,000
Floating rate advances, rates of 2.65% and 1.59%,as of December 31, 2018 and 2017, respectively	150,000	$ 155,000
Total	$ 350,000	$ 155,000

Other Borrowed Funds - Summar_2

Other Borrowed Funds - Summary of advances from the Federal Home Loan Bank (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Average fixed rate advances from FHLB	2.50%
Fixed rate advances maturity date for FHLB	Jan. 28, 2019
Minimum [Member]
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Fixed rate advances from FHLB	2.45%
Floaing rate advances from FHLB	1.59%	1.59%
Maximum [Member]
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Fixed rate advances from FHLB	2.54%
Floaing rate advances from FHLB	2.65%	2.65%

Other Borrowed Funds - Addition

Other Borrowed Funds - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Federal Home Loan Bank advances, maximum eligible amount under collateralized transaction		$ 871,067,000
Debt instrument, maturity date		Apr. 1, 2021
Debt instrument interest description		LIBOR plus 350 basis points
Sunshine Company [Member]
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Debt instrument, maturity date	Apr. 1, 2021
Debt Instrument subscription percentage	100.00%
Debt Instrument, Face Amount	$ 11,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Debt Instrument, Term	5 years
Revolving Line of Credit [Member]
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Line of Credit		$ 0	$ 20,000,000
Line of Credit Facility, Interest Rate			4.84%
Line of credit available		$ 50,000,000
Revolving Line of Credit [Member] | London Interbank Offered Rate (LIBOR)
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Debt instrument variable interst rate		3.50%

Corporate Debentures - Addition

Corporate Debentures - Additional Information (Detail) - USD ($)

Mar. 16, 2016

Dec. 28, 2006

Jul. 17, 2006

Dec. 01, 2004

Sep. 09, 2004

Sep. 22, 2003

Sep. 17, 2003

Dec. 31, 2018

Sep. 30, 2018

Jan. 31, 2018

Nov. 30, 2011

Mar. 31, 2016

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Nov. 01, 2011

Corporate Debenture [Line Items]

Debenture interest rate description

LIBOR plus 350 basis points

Corporate debenture lives

30 years

Corporate debenture callable, Call option period

5 years

Debt instrument maturity year

2,033

Gains (Losses) on Extinguishment of Debt, Total

$ 0

$ 0

$ 308,000

Valrico Bancorp [Member]

Corporate Debenture [Line Items]

Floating rate corporate debenture issued, amount

$ 2,500,000

Debenture interest rate description

three month LIBOR plus 270 bps

Corporate debenture, basis spread on LIBOR rate

2.70%

Corporate debenture lives

30 years

Corporate debenture callable, Call option period

5 years

Gulfstream Bancshares, Inc. [Member]

Corporate Debenture [Line Items]

Floating rate corporate debenture issued, amount

$ 7,000,000

Trust [Member]

Corporate Debenture [Line Items]

Floating rate corporate debenture issued, amount

$ 10,000,000

Trust preferred securities, basis spread on LIBOR rate

3.05%

Debenture interest rate description

three month LIBOR plus 305 basis points

Trust preferred security lives

30 years

Trust preferred securities callable, call option period

5 years

Investment in the common stock of the trust

$ 310,000

Corporate debenture, basis spread on LIBOR rate

3.05%

Valrico Trust [Member] | Valrico Bancorp [Member]

Corporate Debenture [Line Items]

Trust preferred securities, basis spread on LIBOR rate

2.70%

Trust preferred security lives

30 years

Trust preferred securities callable, call option period

5 years

Investment in the common stock of the trust

$ 77,000

Federal Trust Statutory I [Member]

Corporate Debenture [Line Items]

Floating rate corporate debenture issued, amount

$ 5,000,000

Trust preferred securities, basis spread on LIBOR rate

2.95%

Debenture interest rate description

three month LIBOR plus 295 bps

Trust preferred security lives

30 years

Trust preferred securities callable, call option period

5 years

Investment in the common stock of the trust

$ 155,000

Corporate debenture, basis spread on LIBOR rate

2.95%

Corporate debenture lives

30 years

Corporate debenture callable, Call option period

5 years

Gulfstream Bancshares Capital Trust I [Member]

Corporate Debenture [Line Items]

Trust preferred securities, basis spread on LIBOR rate

1.90%

Debenture interest rate description

three month LIBOR plus 190 bps

Trust preferred security lives

30 years

Corporate debenture, basis spread on LIBOR rate

1.90%

Corporate debenture lives

30 years

Gains (Losses) on Extinguishment of Debt, Total

$ 308,000

Gulfstream Bancshares Capital Trust II [Member]

Corporate Debenture [Line Items]

Floating rate corporate debenture issued, amount

$ 3,000,000

Trust preferred securities, basis spread on LIBOR rate

1.70%

Debenture interest rate description

three month LIBOR plus 170 bps

Trust preferred security lives

30 years

Corporate debenture, basis spread on LIBOR rate

1.70%

Corporate debenture lives

30 years

Homestead Statutory Trust I [Member]

Corporate Debenture [Line Items]

Floating rate corporate debenture issued, amount

$ 16,000,000

Trust preferred securities, basis spread on LIBOR rate

1.65%

Debenture interest rate description

three month LIBOR plus 165 bps

Trust preferred security lives

30 years

Corporate debenture, basis spread on LIBOR rate

1.65%

Corporate debenture lives

30 years

Partial redemption of long term debt

$ 6,000,000

BSA Financial Statutory Trust I [Member]

Corporate Debenture [Line Items]

Floating rate corporate debenture issued, amount

$ 5,000,000

Trust preferred securities, basis spread on LIBOR rate

1.55%

Debenture interest rate description

three month LIBOR plus 155 bps

Trust preferred security lives

30 years

Investment in the common stock of the trust

$ 155,000

MRCB Statutory Trust II [Member]

Corporate Debenture [Line Items]

Floating rate corporate debenture issued, amount

$ 3,000,000

Trust preferred securities, basis spread on LIBOR rate

1.60%

Debenture interest rate description

three month LIBOR plus 160 bps

Trust preferred security lives

30 years

Investment in the common stock of the trust

$ 93,000

C B S Financial Capital Trust I

Corporate Debenture [Line Items]

Gains (Losses) on Extinguishment of Debt, Total

$ 0

Acquisition price

$ 4,000,000

CBS Financial Capital Trust II [Member]

Corporate Debenture [Line Items]

Gains (Losses) on Extinguishment of Debt, Total

$ 0

Acquisition price

$ 5,000,000

Income Taxes - Allocation of Fe

Income Taxes - Allocation of Federal and State Income Tax Expense (Benefit) Between Current and Deferred Portions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Current, Federal Tax Expense	$ 14,273	$ 18,243	$ 15,172
Current, State Tax Expense	5,240	4,045	3,091
Current, Total	19,513	22,288	18,263
Deferred, Federal Tax Expense	16,843	29,393	3,127
Deferred, State Tax Expense	4,668	1,799	520
Deferred, Total	21,511	31,192	3,647
Federal, Total	31,116	47,636	18,299
State, Total	9,908	5,844	3,611
Total	$ 41,024	$ 53,480	$ 21,910

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for loan losses	$ 10,079	$ 8,320
Stock based compensation	1,701	1,609
Deferred compensation	2,235	1,488
Impairment expenses	1,334	572
Net operating loss carryforward	18,313	13,278
Other real estate owned expenses	177	557
Fair value adjustments	17,929	13,414
Non-accrual interest	2,890	1,385
Unrealized loss on available for sale debt securities	7,611	2,378
Other		2,339
Total deferred tax assets	62,269	45,340
Deferred tax liabilities:
Other	(107)
Premises and equipment, due to differences in depreciation methods and useful lives	(8,145)	(5,441)
Deferred loan costs, net	(683)	(208)
Prepaid expenses	(1,608)	(1,752)
Like kind exchange	(197)	(197)
Accretion of discounts on investments	(67)	(17)
Total deferred tax liabilities	(10,807)	(7,615)
Net deferred tax asset	$ 51,462	$ 37,725

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 01, 2018	May 01, 2017	Mar. 01, 2016	Jun. 01, 2014
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		$ 51,830
Net operating loss total		71,483
Operating loss carryforwards, valuation allowance		$ 19,653
Operating loss carryforward period	20 years
Revaluation of deferred tax asset due to change in federal income tax rate			$ 18,575
U.S. federal corporate rate		21.00%	35.00%	35.00%
First Southern Bank Inc [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards								$ 57,375
Per year tax credit carryforwards								$ 6,487
Community Bank of South Florida, Inc. [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards							$ 11,526
Per year tax credit carryforwards							1,722
Hometown of Homestead Banking Company [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards							8,763
Per year tax credit carryforwards							$ 507
Accretable Yield [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards						$ 5,407
Per year tax credit carryforwards						$ 3,289
Sunshine Company [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 22,529
Per year tax credit carryforwards	3,682
HCBF Holding Company, Inc. [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	14,003
Per year tax credit carryforwards	$ 1,101
Charter Financial Corporation [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards					$ 3,780
Per year tax credit carryforwards					$ 9,036

Income Taxes - Summary of Net O

Income Taxes - Summary of Net Operating Loss Carryforwards (Details) $ in Thousands	Dec. 31, 2018USD ($)
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 51,830
2027 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	2,418
2028 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	1,996
2029 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	11,826
2030 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	13,681
2031 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	7,246
2032 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	6,841
2033 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	7,063
2035 [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 759

Income Taxes - Reconciliation B

Income Taxes - Reconciliation Between the Actual Tax Expense and the Expected Tax (Benefit) Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
“Expected” tax expense	$ 41,466	$ 38,246	$ 22,488
Tax exempt interest, net	(3,177)	(4,104)	(2,364)
Bank owned life insurance	(1,167)	(1,251)	(825)
State income taxes, net of federal income tax benefits	7,827	4,077	2,347
Stock based compensation	17	40	81
Merger and acquisition related expenses	610	1,049	388
Excess tax benefit from stock based compensation	(5,095)	(3,007)
Revaluation of net deferred tax asset due to change in federal income tax rate		18,575
Other, net	543	(145)	(205)
Total	$ 41,024	$ 53,480	$ 21,910

Related-Party Transactions - Su

Related-Party Transactions - Summary Loans to Principal Officers, Directors and Their Affiliates (Detail) - Principal Officers, Directors and Their Affiliates [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Beginning balance	$ 30,458	$ 26,515
New loans and advances on existing loans	39,183	21,753
Repayments	(21,215)	(17,810)
Ending balance	$ 48,426	$ 30,458

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - Principal Officers, Directors and Their Affiliates [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Line of credit available for principal officers, directors, and their affiliates	$ 10,820	$ 8,835
Deposits from principal officers, directors, and their affiliates	$ 6,739	$ 4,777

Regulatory Capital Matters - Ad

Regulatory Capital Matters - Additional Information (Detail)	Jan. 01, 2019	Dec. 31, 2018	Jan. 02, 2018	Dec. 31, 2017
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier 1 capital (to risk weighted assets), Ratio		11.90%		11.50%
Tier 1 capital (to risk weighted assets), Ratio		12.30%		12.00%
Total capital (to risk weighted assets), Ratio		12.70%		12.60%
Tier 1 capital (to average assets), Ratio		10.00%		9.80%
Capital conservation buffer rate			1.875%
Effective fully implemented, common equity Tier 1 capital ratio		7.00%
Effective fully implemented, total Tier 1 capital ratio		8.50%
Effective fully implemented, total risk-based capital ratio		10.50%
Subsequent Event [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer rate	2.50%
Minimum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier 1 capital (to risk weighted assets), Ratio		4.50%
Tier 1 capital (to risk weighted assets), Ratio		6.00%
Total capital (to risk weighted assets), Ratio		8.00%
Tier 1 capital (to average assets), Ratio		4.00%
Maximum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer rate		2.50%

Regulatory Capital Matters - Su

Regulatory Capital Matters - Summary of Actual, Required, and Capital Levels Necessary for Capital Adequacy Purposes (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk weighted assets), Amount	$ 1,183,229	$ 682,175
Tier 1 capital (to risk weighted assets), Amount	1,143,459	649,350
Common equity tier 1 capital (to risk weighted assets), Amount	1,104,959	621,956
Tier 1 capital (to average assets), Amount	$ 1,143,459	$ 649,350
Total capital (to risk weighted assets), Ratio	12.70%	12.60%
Tier 1 capital (to risk weighted assets), Ratio	12.30%	12.00%
Common equity tier 1 capital (to risk weighted assets), Ratio	11.90%	11.50%
Tier 1 capital (to average assets), Ratio	10.00%	9.80%
Total capital (to risk weighted assets) For capital adequacy purposes, Amount	$ 745,543	$ 434,245
Tier 1 capital (to risk weighted assets) For capital adequacy purposes, Amount	559,157	325,684
Common equity tier 1 capital (to risk weighted assets) For capital adequacy purposes, Amount	419,368	244,263
Tier 1 capital (to average assets) For capital adequacy purposes, Amount	455,561	264,616
CenterState Bank of Florida, N.A. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk weighted assets), Amount	1,177,082	654,018
Tier 1 capital (to risk weighted assets), Amount	1,137,315	621,199
Common equity tier 1 capital (to risk weighted assets), Amount	1,137,315	621,199
Tier 1 capital (to average assets), Amount	$ 1,137,315	$ 621,199
Total capital (to risk weighted assets), Ratio	12.60%	12.20%
Tier 1 capital (to risk weighted assets), Ratio	12.20%	11.50%
Common equity tier 1 capital (to risk weighted assets), Ratio	12.20%	11.50%
Tier 1 capital (to average assets), Ratio	10.00%	9.40%
Total capital (to risk weighted assets) For capital adequacy purposes, Amount	$ 745,003	$ 430,561
Tier 1 capital (to risk weighted assets) For capital adequacy purposes, Amount	558,753	322,921
Common equity tier 1 capital (to risk weighted assets) For capital adequacy purposes, Amount	419,064	242,191
Tier 1 capital (to average assets) For capital adequacy purposes, Amount	455,515	264,577
Total capital (to risk weighted assets) To be well capitalized under Prompt corrective action provision, Amount	931,254	538,202
Tier 1 capital (to risk weighted assets) To be well capitalized under Prompt corrective action provision, Amount	745,003	430,561
Common equity tier 1 capital (to risk weighted assets) To be well capitalized under Prompt corrective action provision, Amount	605,315	349,831
Tier 1 capital (to average assets) To be well capitalized under Prompt corrective action provision, Amount	$ 569,394	$ 330,721
Minimum [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk weighted assets), Ratio	8.00%
Tier 1 capital (to risk weighted assets), Ratio	6.00%
Common equity tier 1 capital (to risk weighted assets), Ratio	4.50%
Tier 1 capital (to average assets), Ratio	4.00%
Total capital (to risk weighted assets) For capital adequacy purposes, Ratio	8.00%	8.00%
Tier 1 capital (to risk weighted assets) For capital adequacy purposes, Ratio	6.00%	6.00%
Common equity tier 1 capital (to risk weighted assets) For capital adequacy purposes, Ratio	4.50%	4.50%
Tier 1 capital (to average assets) For capital adequacy purposes, Ratio	4.00%	4.00%
Minimum [Member] | CenterState Bank of Florida, N.A. [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier 1 capital (to risk weighted assets), Ratio	4.50%	4.50%
Total capital (to risk weighted assets) For capital adequacy purposes, Ratio	8.00%	8.00%
Tier 1 capital (to risk weighted assets) For capital adequacy purposes, Ratio	6.00%	6.00%
Tier 1 capital (to average assets) For capital adequacy purposes, Ratio	4.00%	4.00%
Total capital (to risk weighted assets) To be well capitalized under Prompt corrective action provision, Ratio	10.00%	10.00%
Tier 1 capital (to risk weighted assets) To be well capitalized under Prompt corrective action provision, Ratio	8.00%	8.00%
Common equity tier 1 capital (to risk weighted assets) To be well capitalized under Prompt corrective action provision, Ratio	6.50%	6.50%
Tier 1 capital (to average assets) To be well capitalized under Prompt corrective action provision, Ratio	5.00%	5.00%

Dividends - Additional Informat

Dividends - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Cash dividends declared & paid on common stock	$ 35,906	$ 13,878	$ 7,681
Dividend received from subsidiary banks	68,000	$ 10,000
Available dividends from subsidiary bank	$ 136,124

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)

Apr. 26, 2018

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Sep. 30, 2018

Jan. 01, 2018

Sep. 30, 2017

May 01, 2017

Sep. 30, 2016

Dec. 31, 2015

Sep. 30, 2015

Jan. 17, 2014

Apr. 25, 2013

Apr. 24, 2007

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock options outstanding

655,261

1,119,483

623,490

940,634

Average exercise price of shares outstanding

$ 11.26

$ 11.26

$ 12.30

$ 11.73

Employee incentive stock options, granted

0

0

0

Fair value of restricted stock granted

$ 14.81

Number of shares expected to vest in future

653,212

Income tax benefit provided by share based awards

$ 5,373,000

$ 1,545,000

$ 140,000

Expense Recognized

650,000

624,000

419,000

RSU expense

$ 2,922,000

$ 3,560,000

$ 3,605,000

Director [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock Issued During Period Shares Share Based Compensation

22,074

2018 Equity Incentive Plan [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Maximum number of shares available for issuance

2,200,000

2018 Plan expiration

2,028

Employee incentive stock options, granted

0

Shares available for future grants

2,055,246

2018 Equity Incentive Plan [Member] | Employee [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Employee incentive stock options, granted

0

2018 Equity Incentive Plan [Member] | Maximum [Member] | Director [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Maximum value of shares in grants to be issued

$ 150

2013 Equity Incentive Plan [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Maximum number of shares available for issuance

1,600,000

2013 Equity Incentive Plan [Member] | Employee [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Employee incentive stock options, granted

0

2007 Equity Incentive Plan [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Maximum number of shares available for issuance

1,350,000

2007 Equity Incentive Plan [Member] | Employee [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Employee incentive stock options, granted

0

Stock Option [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Remaining unrecognized compensation cost related to non-vested stock options, net of estimated forfeitures

$ 42,000

Non vested stock options, unrecognized compensation cost, recognition period

4 years

Stock Option [Member] | Weighted Average [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Non vested stock options, unrecognized compensation cost, recognition period

4 years 9 months 18 days

Stock Option [Member] | 2015 Equity Incentive Plan (Sunshine Plan) [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock options outstanding

16,020

590,345

Average exercise price of shares outstanding

$ 15.88

$ 14.84

Stock option expiration period

7 years 3 months 18 days

Stock Option [Member] | 2010 Amended and Restated Stock Incentive Plan (HCBF Plan) [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock options outstanding

145,616

1,621,543

Average exercise price of shares outstanding

$ 15.06

$ 14.80

Stock option expiration period

4 years 9 months 18 days

Stock Option [Member] | Gateway Plans [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock options outstanding

341,425

1,150,517

Average exercise price of shares outstanding

$ 10.70

$ 11.32

Stock option expiration period

4 years 7 months 6 days

Stock Option [Member] | Gulfstream2009 Stock Option Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock options outstanding

52,600

774,104

Average exercise price of shares outstanding

$ 6.72

$ 6.99

Stock option expiration period

3 years 7 months 6 days

Restricted Stock [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of RSAs, granted

67,502

148,232

262,934

Remaining unrecognized compensation cost related to non-vested stock options, net of estimated forfeitures

$ 4,012,000

Non vested stock options, unrecognized compensation cost, recognition period

9 years

Number of RSAs, outstanding

390,366

559,124

699,965

721,715

Number of RSUs, vested

233,947

284,807

279,119

Restricted Stock [Member] | Underlying Shares Issued [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of RSAs, outstanding

50,600

69,700

127,901

189,588

Number of RSUs, vested

19,100

58,201

60,087

Restricted Stock [Member] | Underlying Shares Not Issued [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of RSAs, granted

67,502

148,232

262,934

Number of RSAs, outstanding

339,766

489,424

572,064

532,127

Number of RSUs, vested

214,847

226,606

219,032

Restricted Stock [Member] | Weighted Average [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Non vested stock options, unrecognized compensation cost, recognition period

2 years 4 months 24 days

Restricted Stock [Member] | 2018 Equity Incentive Plan [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of RSAs, granted

67,502

Fair value of restricted stock granted

$ 26.77

Restricted Stock [Member] | 2018 Equity Incentive Plan [Member] | Maximum [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Restricted stock awards vesting period

5 years

Restricted Stock [Member] | 2018 Equity Incentive Plan [Member] | Minimum [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Restricted stock awards vesting period

2 years

Performance Share Units [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Remaining unrecognized compensation cost related to non-vested stock options, net of estimated forfeitures

$ 1,674,000

Non vested stock options, unrecognized compensation cost, recognition period

3 years

Total PSUs approved by compensation committee

157,020

Expense Recognized

$ 520,000

Performance Share Units [Member] | Grant Year 2015 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Compensation Not yet Recognized, Share-based Awards Other than Options, PSUs

$ 307,000

Performance Share Units [Member] | Grant Year 2016 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Compensation Not yet Recognized, Share-based Awards Other than Options, PSUs

$ 412,000

Performance Share Units [Member] | Grant Year 2017 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Compensation Not yet Recognized, Share-based Awards Other than Options, PSUs

$ 687,000

Performance Share Units [Member] | Grant Year 2018 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Compensation Not yet Recognized, Share-based Awards Other than Options, PSUs

$ 1,134,000

Performance Share Units [Member] | Weighted Average [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Non vested stock options, unrecognized compensation cost, recognition period

1 year 9 months 18 days

Performance Share Units [Member] | 2018 Equity Incentive Plan [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Performance share units vesting date

Jan. 1, 2022

Number of shares expected to vest in future

48,435

Performance Share Units [Member] | 2018 Equity Incentive Plan [Member] | Maximum [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares expected to vest in future

72,655

Performance Share Units [Member] | 2018 Equity Incentive Plan [Member] | Minimum [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares expected to vest in future

0

Restricted Stock Units [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of RSAs, granted

41,630

32,441

28,725

Remaining unrecognized compensation cost related to non-vested stock options, net of estimated forfeitures

$ 1,601,000

Non vested stock options, unrecognized compensation cost, recognition period

3 years

Number of RSAs, outstanding

128,447

86,817

54,376

29,092

RSU expense

$ 538,000

$ 287,000

$ 169,000

Restricted Stock Units [Member] | Grant Year 2015 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Compensation Not yet Recognized, Share-based Awards Other than Options, PSUs

$ 356,000

Restricted Stock Units [Member] | Grant Year 2016 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Compensation Not yet Recognized, Share-based Awards Other than Options, PSUs

442,000

Number of RSUs, vested

3,441

Restricted Stock Units [Member] | Grant Year 2017 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Compensation Not yet Recognized, Share-based Awards Other than Options, PSUs

$ 720,000

Restricted Stock Units [Member] | Grant Year 2018 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Compensation Not yet Recognized, Share-based Awards Other than Options, PSUs

$ 1,107,000

Restricted Stock Units [Member] | Weighted Average [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Non vested stock options, unrecognized compensation cost, recognition period

1 year 9 months 18 days

Restricted Stock Units [Member] | Vest in January 1, 2020 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Vesting percentage for each year

33.33%

Restricted Stock Units [Member] | Vest in January 1, 2021 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Vesting percentage for each year

33.33%

Restricted Stock Units [Member] | Vest in January 1, 2022 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Vesting percentage for each year

33.33%

Restricted Stock Units [Member] | 2018 Equity Incentive Plan [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of RSAs, granted

41,630

Fair value of restricted stock granted

$ 26.60

Qualified Incentive Stock Options [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Income tax benefit provided by share based awards

$ 0

Non Qualified Incentive Stock Options [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Income tax benefit provided by share based awards

5,373,000

1,545,000

$ 140,000

RSA,RSU and PSU [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Income tax benefit provided by share based awards

1,042,000

$ 1,725,000

$ 1,617,000

Performance Share Units Division | Grant Year 2016 [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Compensation Not yet Recognized, Share-based Awards Other than Options, PSUs

$ 192,000

Expense Recognized

$ 130,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Based Compensation Expense Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option expense	$ 83	$ 115	$ 230
Stock-based compensation expense	2,922	3,560	3,605
PSU expense	650	624	419
Total stock-based compensation expense	4,193	4,586	4,423
RSU Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 538	$ 287	$ 169

Stock-Based Compensation - Info

Stock-Based Compensation - Information Related to Stock Option Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Total intrinsic value of stock options exercised	$ 1,492	$ 8,039	$ 2,716
Net proceeds from stock options exercised	14,707	6,715	1,769
Gross income tax benefit from the exercise of stock options	$ 5,373	$ 1,545	$ 140

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options outstanding, beginning of period, Number of Options	1,119,483	623,490	940,634
Options assumed pursuant to acquisition of (note 1):
Options exercised, Number of Options	(1,793,339)	(598,039)	(229,583)
Options forfeited, Number of Options	(882,771)	(56,485)	(87,561)
Options outstanding, end of period, Number of Options	655,261	1,119,483	623,490
Options outstanding, beginning of period, Weighted-Average Exercise Price	$ 11.26	$ 12.30	$ 11.73
Options exercised, Weighted-Average Exercise Price	13.61	12.11	8.74
Options forfeited, Weighted-Average Exercise Price	15.37	15	15.51
Options outstanding, end of period, Weighted-Average Exercise Price	$ 11.26	$ 11.26	$ 12.30
Gateway [Member]
Options assumed pursuant to acquisition of (note 1):
Options assumed pursuant to acquisition of (note 1):, Number of Options		1,150,517
Options assumed pursuant to acquisition of (note 1):, Weighted-Average Exercise Price		$ 11.32
HCBF [Member]
Options assumed pursuant to acquisition of (note 1):
Options assumed pursuant to acquisition of (note 1):, Number of Options	1,621,543
Options assumed pursuant to acquisition of (note 1):, Weighted-Average Exercise Price	$ 14.80
Sunshine [Member]
Options assumed pursuant to acquisition of (note 1):
Options assumed pursuant to acquisition of (note 1):, Number of Options	590,345
Options assumed pursuant to acquisition of (note 1):, Weighted-Average Exercise Price	$ 14.84

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Outstanding, Vested and Expected to Vest and Exercisable Stock Options (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, Number of options	655,261	1,119,483	623,490	940,634
Options fully vested and expected to vest, Number of Options	653,212
Options exercisable, Number of Options	626,401
Options outstanding, Weighted-Average Exercise Price	$ 11.26	$ 11.26	$ 12.30	$ 11.73
Options fully vested and expected to vest, Weighted Average Exercise Price	11.27
Options exercisable, Weighted-Average Exercise Price	$ 11.37
Options outstanding, Weighted-Average Contractual Term	4 years 2 months 12 days
Options fully vested and expected to vest, Weighted-Average Contractual Term	4 years 2 months 12 days
Options exercisable, Weighted-Average Contractual Term	4 years 3 months 18 days
Options outstanding, Aggregate Intrinsic Value	$ 6,412
Options fully vested and expected to vest, Aggregate Intrinsic Value	6,381
Options exercisable, Aggregate Intrinsic Value	$ 6,051

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Restricted Stock Awards Activity (Detail) - Restricted Stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Awards and Units outstanding, beginning of period	559,124	699,965	721,715
Number of Awards and Units, Granted	67,502	148,232	262,934
Number of Awards and Units, Vested	(233,947)	(284,807)	(279,119)
Number of Awards and Units, Forfeited	(2,313)	(4,266)	(5,565)
Number of Awards and Units, outstanding, end of period	390,366	559,124	699,965
Weighted-Average fair value at grant date of Award and Units, outstanding, beginning of period	$ 15.89	$ 12.20	$ 10.79
Weighted-Average fair value at grant date of Award and Units, Granted	26.77	24.94	14.68
Weighted-Average fair value at grant date of Award and Units, Vested	13.65	11.52	10.88
Weighted-Average fair value at grant date of Award and Units, Forfeited	18.55	15.76	12.07
Weighted-Average fair value at grant date of Award and Units, ending of period	$ 19.10	$ 15.89	$ 12.20
Underlying Shares Not Issued [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Awards and Units outstanding, beginning of period	489,424	572,064	532,127
Number of Awards and Units, Granted	67,502	148,232	262,934
Number of Awards and Units, Vested	(214,847)	(226,606)	(219,032)
Number of Awards and Units, Forfeited	(2,313)	(4,266)	(3,965)
Number of Awards and Units, outstanding, end of period	339,766	489,424	572,064
Underlying Shares Issued [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Awards and Units outstanding, beginning of period	69,700	127,901	189,588
Number of Awards and Units, Vested	(19,100)	(58,201)	(60,087)
Number of Awards and Units, Forfeited			(1,600)
Number of Awards and Units, outstanding, end of period	50,600	69,700	127,901

Stock-Based Compensation - Su_5

Stock-Based Compensation - Summary of Restricted Stock Units (Detail) - Restricted Stock Units [Member] - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Awards and Units outstanding, beginning of period	86,817	54,376	29,092
Number of Awards and Units, Granted	41,630	32,441	28,725
Number of Awards and Units, Vested and Issued			(3,441)
Number of Awards and Units, outstanding, end of period	128,447	86,817	54,376
Weighted-Average fair value at grant date of Award and Units, outstanding, beginning of period	$ 17	$ 14	$ 12.22
Weighted-Average fair value at grant date of Award and Units, Granted	26.60	22.19	15.37
Weighted-Average fair value at grant date of Award and Units, Vested and Issued			12.22
Weighted-Average fair value at grant date of Award and Units, ending of period	$ 20	$ 17	$ 14

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2010Officers	Dec. 31, 2007Officers	Dec. 31, 2015USD ($)
Compensation And Retirement Disclosure [Abstract]
Company's contributions for the plan	$ 3,444	$ 2,249	$ 1,849
Eligibility period to participate in the plan	6 months
Additional number of executive officers entered into salary continuation agreements | Officers				5
Number of executive officers entered into salary continuation agreements due to acquisition | Officers					4
Company expensed for the accrual of future salary continuation benefits	$ 641	568	609
Salary continuation benefits payable		7,966	4,834			$ 4,211
Asset and the related deferred compensation payable	307	$ 1,761	$ 1,560
Administration expenses of the trust	$ 5
Number of Valrico state bank executive officers pursuant to acquisition entered into rabbi trust agreement | Officers					2

Parent Company Only Financial_3

Parent Company Only Financial Statements - Condensed Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets:
Cash and due from banks	$ 107,007	$ 68,571
Prepaid expenses and other assets	31,219	64,022
TOTAL ASSETS	12,337,588	7,123,975	$ 5,078,559
Liabilities:
Accounts payable and accrued expenses	47,842	29,512
Corporate debentures	32,415	26,192
Total liabilities	10,366,244	6,219,225
Stockholders' equity:
Common stock	957	602
Additional paid-in capital	1,699,031	737,905
Retained earnings	293,777	173,248
Accumulated other comprehensive income	(22,421)	(7,005)
Total stockholders’ equity	1,971,344	904,750	$ 552,457	$ 490,514
Total liabilities and stockholders' equity	12,337,588	7,123,975
Parent Company [Member]
Assets:
Cash and due from banks	1,338	1,569
Inter-company receivable from bank subsidiary	2,340	840
Investment in wholly-owned bank subsidiary	1,999,963	903,882
Investment in other wholly-owned subsidiary	2,761	1,951
Prepaid expenses and other assets	10,506	49,011
TOTAL ASSETS	2,016,908	957,253
Liabilities:
Accounts payable and accrued expenses	2,149	6,311
Other borrowings	11,000	20,000
Corporate debentures	32,415	26,192
Total liabilities	45,564	52,503
Stockholders' equity:
Common stock	957	602
Additional paid-in capital	1,699,031	737,905
Retained earnings	293,777	173,248
Accumulated other comprehensive income	(22,421)	(7,005)
Total stockholders’ equity	1,971,344	904,750
Total liabilities and stockholders' equity	$ 2,016,908	$ 957,253

Parent Company Only Financial_4

Parent Company Only Financial Statements - Condensed Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements Captions [Line Items]
Interest expense	$ (47,550)	$ (15,783)	$ (9,340)
Net income before income tax benefit	197,459	109,275	64,251
Income tax benefit	41,024	53,480	21,910
Net income	156,435	55,795	42,341
Parent Company [Member]
Condensed Financial Statements Captions [Line Items]
Dividend income	68,000	10,000	58,000
Other income	8		308
Interest expense	(3,415)	(1,363)	(1,159)
Operating expenses	(3,988)	(3,960)	(3,869)
Income before equity in undistributed income of subsidiaries	60,605	4,677	53,280
Equity in undistributed income (losses) of subsidiaries	88,532	48,760	(12,736)
Net income before income tax benefit	149,137	53,437	40,544
Income tax benefit	(7,298)	(2,358)	(1,797)
Net income	$ 156,435	$ 55,795	$ 42,341

Parent Company Only Financial_5

Parent Company Only Financial Statements - Condensed Statements of Cash Flows (Detail) - USD ($) $ in Thousands	Jan. 13, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income		$ 156,435	$ 55,795	$ 42,341
Adjustments to reconcile net income to net cash used in operating activities:
Gain on extinguishment of debt		0	0	(308)
(Increase) decrease in other assets		61,575	(48,145)	(3,585)
Stock based compensation expense		4,193	4,586	4,423
Net cash provided by operating activities		193,438	22,757	36,745
Cash flows from investing activities:
Net cash used in investing activities		(87,994)	(281,271)	(235,253)
Cash flows from financing activities:
Stock options exercised		14,707	6,715	1,769
Stock repurchased		(1,027)	(1,131)	(962)
Extinguishment of debt		0	0	(8,680)
(Decrease) increase in other borrowings		(77,920)	40,268	(57,418)
Proceeds from stock offering, net of offering costs	$ 63,262	0	63,262	0
Dividends paid to shareholders		(35,906)	(13,878)	(7,681)
Net cash (used in) provided by financing activities		(18,730)	363,479	221,680
Cash and cash equivalents at beginning of year		280,619
Cash and cash equivalents at end of year		367,333	280,619
Parent Company [Member]
Cash flows from operating activities:
Net income		156,435	55,795	42,341
Adjustments to reconcile net income to net cash used in operating activities:
Undistributed net (earnings) losses of subsidiaries		(88,532)	(48,760)	70,736
Increase in payables and accrued expenses		(13,385)	463	(25)
Gain on extinguishment of debt				(308)
(Increase) decrease in other assets		3,998	(40,369)	84
Stock based compensation expense			1,048	1,001
Net cash provided by operating activities		58,516	(31,823)	113,829
Cash flows from investing activities:
Inter-company receivables from subsidiary bank		(473)	25,145	(58,241)
Net cash from bank acquisitions		(36,037)	(42,601)	(38,918)
Investment in subsidiaries			(25,000)	450
Cash payments to shareholders		19,339	(90)	39
Net cash used in investing activities		(17,171)	(42,546)	(96,670)
Cash flows from financing activities:
Stock options exercised		14,707	6,715	1,769
Stock repurchased		(1,027)	(1,131)	(962)
Stock issuance		650
Extinguishment of debt				(8,680)
(Decrease) increase in other borrowings		(20,000)	20,000	(650)
Proceeds from stock offering, net of offering costs			63,262
Dividends paid to shareholders		(35,906)	(13,878)	(7,681)
Net cash (used in) provided by financing activities		(41,576)	74,968	(16,204)
Net increase (decrease) in cash and cash equivalents		(231)	599	955
Cash and cash equivalents at beginning of year		1,569	970	15
Cash and cash equivalents at end of year		$ 1,338	$ 1,569	$ 970

Credit Commitments - Summary of

Credit Commitments - Summary of Credit Commitments (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Standby Letters of Credit [Member]
Loss Contingencies [Line Items]
Credit Commitments, Total	$ 28,964	$ 15,740
Unfunded Loan Commitments - Fixed [Member]
Loss Contingencies [Line Items]
Credit Commitments, Total	153,680	140,750
Unfunded Loan Commitments - Variable [Member]
Loss Contingencies [Line Items]
Credit Commitments, Total	65,880	35,814
Available Lines of Credit [Member]
Loss Contingencies [Line Items]
Credit Commitments, Total	$ 1,514,359	$ 824,958

Credit Commitments - Additional

Credit Commitments - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018
Loss Contingencies [Line Items]
Loan commitments period	30 days
Minimum [Member]
Loss Contingencies [Line Items]
Loan commitments percentage of fixed interest rate	3.27%
Loan commitments fixed interest rate, maturity term	1 year
Maximum [Member]
Loss Contingencies [Line Items]
Loan commitments percentage of fixed interest rate	8.35%
Loan commitments fixed interest rate, maturity term	20 years

Basic and Diluted Earnings Pe_3

Basic and Diluted Earnings Per Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Anti dilutive stock options	0	0	24,500

Basic and Diluted Earnings Pe_4

Basic and Diluted Earnings Per Share - Factors Used in Earnings Per Share Computations (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic
Net income available to common shareholders		$ 156,435	$ 55,795	$ 42,341
Less: Earnings allocated to participating securities		(116)	(120)	(163)
Net income allocated to common shareholders		$ 156,319	$ 55,675	$ 42,178
Weighted average common shares outstanding including participating securities		87,707,196	57,368,322	47,592,500
Less: Participating securities	[1]	(65,976)	(123,624)	(183,358)
Average shares	[2]	87,641,220	57,244,698	47,409,142
Basic earnings per common share		$ 1.78	$ 0.97	$ 0.89
Diluted
Net income available to common shareholders		$ 156,319	$ 55,675	$ 42,178
Weighted average common shares outstanding for basic earnings per common share	[2]	87,641,220	57,244,698	47,409,142
Add: Dilutive effects of stock based compensation awards		1,117,633	1,096,115	782,381
Average shares and dilutive potential common shares	[2]	88,758,853	58,340,813	48,191,523
Dilutive earnings per common share		$ 1.76	$ 0.95	$ 0.88
[1]	Participating securities are restricted stock awards whereby the stock certificates have been issued, are included in outstanding shares, receive dividends and can be voted, but have not vested.
[2]	Excludes participating securities.

Reportable Segments - Reconcili

Reportable Segments - Reconciliation of Reportable Segment Revenues, Expenses and Profit (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Interest income	$ 460,632	$ 251,326	$ 188,665
Interest expense	(47,550)	(15,783)	(9,340)
Net interest income	413,082	235,543	179,325
Provision for loan losses	(8,283)	(4,958)	(4,962)
Non-interest income	105,127	65,175	64,369
Non-interest expense	(312,467)	(186,485)	(174,481)
Net income before income tax benefit	197,459	109,275	64,251
Income tax (provision) benefit	(41,024)	(53,480)	(21,910)
Net income	156,435	55,795	42,341
Total assets	12,337,588	7,123,975	5,078,559
Operating Segments [Member] | Commercial and Retail Banking [Member]
Segment Reporting Information [Line Items]
Interest income	445,688	240,583	180,696
Interest expense	(36,853)	(11,431)	(7,044)
Net interest income	408,835	229,152	173,652
Provision for loan losses	(7,914)	(5,037)	(4,938)
Non-interest income	71,731	36,834	30,376
Non-interest expense	(286,191)	(161,946)	(147,228)
Net income before income tax benefit	186,461	99,003	51,862
Income tax (provision) benefit	(43,662)	(49,823)	(17,107)
Net income	142,799	49,180	34,755
Total assets	11,769,734	6,572,636	4,676,375
Operating Segments [Member] | Correspondent Banking And Capital Markets Division [Member]
Segment Reporting Information [Line Items]
Interest income	14,944	10,743	7,969
Interest expense	(7,282)	(2,989)	(1,137)
Net interest income	7,662	7,754	6,832
Provision for loan losses	(369)	79	(24)
Non-interest income	33,388	28,341	33,685
Non-interest expense	(22,288)	(20,579)	(23,384)
Net income before income tax benefit	18,393	15,595	17,109
Income tax (provision) benefit	(4,660)	(6,015)	(6,600)
Net income	13,733	9,580	10,509
Total assets	561,885	506,234	397,323
Corporate Overhead and Administration [Member]
Segment Reporting Information [Line Items]
Interest expense	(3,415)	(1,363)	(1,159)
Net interest income	(3,415)	(1,363)	(1,159)
Non-interest income	8		308
Non-interest expense	(3,988)	(3,960)	(3,869)
Net income before income tax benefit	(7,395)	(5,323)	(4,720)
Income tax (provision) benefit	7,298	2,358	1,797
Net income	(97)	(2,965)	(2,923)
Total assets	2,016,908	957,253	584,572
Elimination Entries [Member]
Segment Reporting Information [Line Items]
Total assets	$ (2,010,939)	$ (912,148)	$ (579,711)

Business Combinations - Additio

Business Combinations - Additional Information (Detail) $ / shares in Units, $ in Thousands	Sep. 01, 2018USD ($)$ / shares	Jan. 01, 2018USD ($)$ / shares	May 01, 2017USD ($)$ / shares	Apr. 01, 2017USD ($)$ / shares	Dec. 31, 2018USD ($)Location	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Nov. 23, 2018	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Goodwill on the acquisition					$ 802,880	$ 257,683	$ 106,028		$ 76,739
Goodwill					802,880	257,683	106,028		$ 76,739
Total assets					12,337,588	7,123,975	5,078,559
Total deposits					$ 9,477,336	5,560,523
National Commerce Corporation [Member]
Business Acquisition [Line Items]
Number of operating locations of bank | Location					37
Total assets					$ 4,210,541
Gross Loans					3,317,965
Total deposits					$ 3,432,289
Maximum [Member]
Business Acquisition [Line Items]
Estimated economic life					5 years
Minimum [Member]
Business Acquisition [Line Items]
Estimated economic life					3 years
Core Deposits [Member]
Business Acquisition [Line Items]
Estimated economic life					10 years
Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Effective date of acquisition					Apr. 1, 2017
Increase in total assets				14.00%
Increase in total deposits				13.00%
Merger and acquisition related expenses					$ 0	3,924	$ 186
Goodwill on the acquisition				$ 73,829
Multiplied by the cash consideration each Platinum share is entitled to receive | $ / shares				$ 7.60
Per share exchange ratio				3.7832
Acquisition price				$ 119,431
Loans at fair value				454,584
Estimated discount on loans acquired				$ 8,980
Estimated discount to outstanding principal balance				1.90%
Percentage of loans acquired							13.30%
Cash consideration each share is entitled to receive | $ / shares				$ 7.60
Goodwill				$ 73,829
Platinum Bank Holding Company [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Deposit intangible asset				3,992
Platinum Bank Holding Company [Member] | Core Deposits [Member] | Maximum [Member]
Business Acquisition [Line Items]
Estimated economic life					10 years
Platinum Bank Holding Company [Member] | Purchased Credit-Impaired [Member]
Business Acquisition [Line Items]
Loans with credit deficiencies				$ 12,218
Platinum Bank Holding Company [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Outstanding common stock acquired percentage				100.00%
Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Effective date of acquisition					May 1, 2017
Increase in total assets			19.00%
Increase in total deposits			17.00%
Merger and acquisition related expenses					$ 149	6,203	$ 11
Goodwill on the acquisition			$ 77,826
Multiplied by the cash consideration each Platinum share is entitled to receive | $ / shares			$ 18
Per share exchange ratio			0.95
Acquisition price			$ 157,372
Loans at fair value			568,240
Estimated discount on loans acquired			$ 9,479
Estimated discount to outstanding principal balance			1.60%
Percentage of loans acquired							16.60%
Cash consideration each share is entitled to receive | $ / shares			$ 18
Goodwill			$ 77,826
Gateway Financial Holdings Of Florida Inc [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Deposit intangible asset			8,432
Gateway Financial Holdings Of Florida Inc [Member] | Core Deposits [Member] | Maximum [Member]
Business Acquisition [Line Items]
Estimated economic life					10 years
Gateway Financial Holdings Of Florida Inc [Member] | Purchased Credit-Impaired [Member]
Business Acquisition [Line Items]
Loans with credit deficiencies			$ 7,827
Gateway Financial Holdings Of Florida Inc [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Outstanding common stock acquired percentage			100.00%
Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Effective date of acquisition		Jan. 1, 2018
Increase in total assets		14.00%
Increase in total deposits		13.00%
Merger and acquisition related expenses					$ 10,474	$ 859
Goodwill on the acquisition		$ 114,228
Per share exchange ratio		0.89
Acquisition price		$ 187,852
Loans at fair value		684,322
Estimated discount on loans acquired		$ 22,657
Estimated discount to outstanding principal balance		3.20%
Percentage of loans acquired						14.30%
Goodwill, period decrease					4,114	$ 4,114
Income tax expense, related to goodwill					$ 1,397	1,397
Goodwill		$ 114,228
Sunshine Bancorp, Inc. [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Deposit intangible asset		8,525
Sunshine Bancorp, Inc. [Member] | Core Deposits [Member] | Maximum [Member]
Business Acquisition [Line Items]
Estimated economic life					10 years
Sunshine Bancorp, Inc. [Member] | Purchased Credit-Impaired [Member]
Business Acquisition [Line Items]
Loans with credit deficiencies		$ 8,232
Sunshine Bancorp, Inc. [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Outstanding common stock acquired percentage		100.00%
HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Effective date of acquisition		Jan. 1, 2018
Increase in total assets		33.00%
Increase in total deposits		32.00%
Merger and acquisition related expenses					$ 12,302	$ 2,060
Goodwill on the acquisition		$ 233,321
Multiplied by the cash consideration each Platinum share is entitled to receive | $ / shares		$ 1.925
Per share exchange ratio		0.675
Acquisition price		$ 448,236
Loans at fair value		1,326,035
Estimated discount on loans acquired		$ 40,438
Estimated discount to outstanding principal balance		30.00%
Percentage of loans acquired						278.00%
Cash consideration each share is entitled to receive | $ / shares		$ 1.925
Goodwill		$ 233,321
HCBF Holding Company, Inc. [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Deposit intangible asset		23,625
HCBF Holding Company, Inc. [Member] | Core Deposits [Member] | Maximum [Member]
Business Acquisition [Line Items]
Estimated economic life					10 years
HCBF Holding Company, Inc. [Member] | Purchased Credit-Impaired [Member]
Business Acquisition [Line Items]
Loans with credit deficiencies		$ 36,031
HCBF Holding Company, Inc. [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Outstanding common stock acquired percentage		100.00%
Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Effective date of acquisition	Sep. 1, 2018
Increase in total assets	24.00%
Increase in total deposits	24.00%
Merger and acquisition related expenses					$ 11,987
Goodwill on the acquisition	$ 197,648
Multiplied by the cash consideration each Platinum share is entitled to receive | $ / shares	$ 2.30
Per share exchange ratio	0.738
Acquisition price	$ 389,476
Loans at fair value	1,141,672
Estimated discount on loans acquired	$ 23,118
Estimated discount to outstanding principal balance	2.00%
Percentage of loans acquired						23.90%
Cash consideration each share is entitled to receive | $ / shares	$ 2.30
Goodwill	$ 197,648
Determination period for fair value estimates	1 year
Charter Financial Corporation [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Deposit intangible asset	$ 19,795
Charter Financial Corporation [Member] | Core Deposits [Member] | Maximum [Member]
Business Acquisition [Line Items]
Estimated economic life					10 years
Charter Financial Corporation [Member] | Purchased Credit-Impaired [Member]
Business Acquisition [Line Items]
Loans with credit deficiencies	$ 11,432
Charter Financial Corporation [Member] | Common Stock [Member]
Business Acquisition [Line Items]
Outstanding common stock acquired percentage	100.00%
National Commerce Corporation [Member]
Business Acquisition [Line Items]
Per share exchange ratio								1.65

Business Combinations - Summary

Business Combinations - Summary of Purchase Price Calculation (Detail) $ / shares in Units, $ in Thousands	Sep. 01, 2018USD ($)$ / sharesshares	Jan. 01, 2018USD ($)$ / sharesshares	May 01, 2017USD ($)$ / sharesshares	Apr. 01, 2017USD ($)$ / sharesshares
Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Number of shares of common stock outstanding | shares				1,131,134
Per share exchange ratio				3.7832
Number of shares of CenterState common stock less fractional shares | shares				4,279,255
CenterState common stock price per share | $ / shares				$ 25.90
Fair value of CenterState common stock issued				$ 110,833
Cash consideration each share is entitled to receive | $ / shares				$ 7.60
Total cash consideration, not including cash for fractional shares				$ 8,597
Total cash consideration				8,598
Total purchase price				$ 119,431
Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Number of shares of common stock outstanding | shares			5,463,764
Preferred shares that converted to common shares upon a change in control | shares			919,236
Total common shares including conversion of preferred shares | shares			6,383,000
Number of shares of common shares exchanged for CenterState common stock | shares			4,468,100
Per share exchange ratio			0.95
Number of shares of CenterState common stock less fractional shares | shares			4,244,441
CenterState common stock price per share | $ / shares			$ 25.23
Fair value of CenterState common stock issued			$ 107,087
Number of common shares exchanged for cash | shares			1,914,900
Cash consideration each share is entitled to receive | $ / shares			$ 18
Total cash consideration, not including cash for fractional shares			$ 34,468
Total cash consideration			34,474
Total consideration paid to Gateway common shareholders			141,561
Fair value of Gateway stock options converted to CenterState stock options			15,811
Total purchase price			$ 157,372
Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Number of shares of common stock outstanding | shares		7,922,479
Per share exchange ratio		0.89
Number of shares of CenterState common stock less fractional shares | shares		7,050,645
CenterState common stock price per share | $ / shares		$ 25.73
Fair value of CenterState common stock issued		$ 181,413
Total cash consideration		7
Total consideration paid to Gateway common shareholders		181,420
Fair value of Gateway stock options converted to CenterState stock options		6,432
Total purchase price		$ 187,852
HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Number of shares of common stock outstanding | shares		22,299,082
Per share exchange ratio		0.675
Number of shares of CenterState common stock less fractional shares | shares		15,051,639
CenterState common stock price per share | $ / shares		$ 25.73
Fair value of CenterState common stock issued		$ 387,279
Number of common shares exchanged for cash | shares		22,299,082
Cash consideration each share is entitled to receive | $ / shares		$ 1.925
Total cash consideration, not including cash for fractional shares		$ 42,932
Total cash consideration		42,932
Total consideration paid to Gateway common shareholders		430,211
Fair value of Gateway stock options converted to CenterState stock options		18,025
Total purchase price		$ 448,236
Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Number of shares of common stock outstanding | shares	15,480,776
Per share exchange ratio	0.738
Number of shares of CenterState common stock less fractional shares | shares	11,424,214
CenterState common stock price per share | $ / shares	$ 30.62
Fair value of CenterState common stock issued	$ 349,809
Cash consideration each share is entitled to receive | $ / shares	$ 2.30
Total cash consideration, not including cash for fractional shares	$ 35,624
Total cash consideration	35,624
Total consideration paid to Gateway common shareholders	385,433
Total purchase price	389,476
Cash out of Charter stock options	$ 4,043

Business Combinations - Summa_2

Business Combinations - Summary of Purchase Price Calculation (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 01, 2018	Jan. 01, 2018	May 01, 2017	Apr. 01, 2017
Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Fractional shares				51
Fractional shares amount				$ 1
Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Fractional shares			254
Fractional shares amount			$ 6
Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Fractional shares		361
HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Fractional shares		241
Fractional shares amount		$ 6
Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Fractional shares	599
Fractional shares amount	$ 17

Business Combinations - Summa_3

Business Combinations - Summary of Preliminary Estimates of Fair Value of Assets Purchased, Including Goodwill and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	May 01, 2017	Apr. 01, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets:
Goodwill	$ 802,880	$ 257,683			$ 106,028	$ 76,739
Platinum Bank Holding Company [Member]
Assets:
Cash and cash equivalents				$ 106,537
Loans, held for investment				442,366
Purchased credit impaired loans				12,218
Investments				28,873
Accrued interest receivable				1,216
Branch real estate				9,600
Furniture and fixtures				402
Bank property held for sale				4,382
FHLB stock				2,220
Other repossessed real estate owned				272
Core deposit intangible				3,992
Goodwill				73,829
Deferred tax asset				227
Other assets				29
Total assets acquired				686,163
Liabilities:
Deposits				520,423
Federal Home Loan Bank advances				40,546
Securities sold under agreement to repurchase				5,569
Accrued interest payable				94
Other liabilities				100
Total liabilities assumed				$ 566,732
Gateway Financial Holdings Of Florida Inc [Member]
Assets:
Cash and cash equivalents			$ 23,065
Loans, held for investment			560,413
Purchased credit impaired loans			7,827
Investments			231,951
Accrued interest receivable			2,422
Branch real estate			18,160
Furniture and fixtures			702
Bank property held for sale			1,087
Other repossessed real estate owned			134
Bank owned life insurance			15,475
Servicing asset intangible			271
Core deposit intangible			8,432
Goodwill			77,826
Deferred tax asset			7,246
Other assets			1,217
Total assets acquired			960,868
FHLB and FRB stock			4,640
Liabilities:
Deposits			708,209
Federal Home Loan Bank advances			90,598
Federal funds purchased			3,588
Accrued interest payable			304
Other liabilities			797
Total liabilities assumed			$ 803,496

Business Combinations - Summa_4

Business Combinations - Summary of Contractually Required Principal and Interest Cash Payments for Purchased Credit Impaired Loans (Detail) - Purchased Credit-Impaired [Member] - USD ($) $ in Thousands	Sep. 01, 2018	Jan. 01, 2018	May 01, 2017	Apr. 01, 2017
Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Contractually required principal and interest				$ 18,811
Non-accretable difference				(4,639)
Cash flows expected to be collected				14,172
Accretable yield				(1,954)
Total purchased credit-impaired loans acquired				$ 12,218
Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Contractually required principal and interest			$ 12,523
Non-accretable difference			(2,465)
Cash flows expected to be collected			10,058
Accretable yield			(2,231)
Total purchased credit-impaired loans acquired			$ 7,827
Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Contractually required principal and interest		$ 21,598
Non-accretable difference		(12,213)
Cash flows expected to be collected		9,385
Accretable yield		(1,153)
Total purchased credit-impaired loans acquired		8,232
HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Contractually required principal and interest		67,107
Non-accretable difference		(25,951)
Cash flows expected to be collected		41,156
Accretable yield		(5,125)
Total purchased credit-impaired loans acquired		$ 36,031
Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Contractually required principal and interest	$ 33,687
Non-accretable difference	(20,763)
Cash flows expected to be collected	12,924
Accretable yield	(1,492)
Total purchased credit-impaired loans acquired	$ 11,432

Business Combinations - Summa_5

Business Combinations - Summary of Fair Value of Acquired Loans and Unpaid Principal Balance (Detail) - USD ($) $ in Thousands	Sep. 01, 2018	Jan. 01, 2018	May 01, 2017	Apr. 01, 2017
Fair Value [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				$ 454,584
Fair Value [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			$ 568,240
Fair Value [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		$ 684,322
Fair Value [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		1,326,035
Fair Value [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	$ 1,141,672
Fair Value [Member] | Residential Real Estate [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				37,419
Fair Value [Member] | Residential Real Estate [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			142,468
Fair Value [Member] | Residential Real Estate [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		146,057
Fair Value [Member] | Residential Real Estate [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		363,559
Fair Value [Member] | Residential Real Estate [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	280,200
Fair Value [Member] | Commercial Real Estate [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				259,727
Fair Value [Member] | Commercial Real Estate [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			317,578
Fair Value [Member] | Commercial Real Estate [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		371,323
Fair Value [Member] | Commercial Real Estate [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		627,900
Fair Value [Member] | Commercial Real Estate [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	557,730
Fair Value [Member] | Land, Development, Construction [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				46,618
Fair Value [Member] | Land, Development, Construction [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			46,489
Fair Value [Member] | Land, Development, Construction [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		57,331
Fair Value [Member] | Land, Development, Construction [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		146,639
Fair Value [Member] | Land, Development, Construction [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	178,687
Fair Value [Member] | Commercial and Industrial [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				95,701
Fair Value [Member] | Commercial and Industrial [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			46,274
Fair Value [Member] | Commercial and Industrial [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		99,650
Fair Value [Member] | Commercial and Industrial [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		110,630
Fair Value [Member] | Commercial and Industrial [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	87,062
Fair Value [Member] | Consumer and Other [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				2,901
Fair Value [Member] | Consumer and Other [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			7,604
Fair Value [Member] | Consumer and Other [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		1,729
Fair Value [Member] | Consumer and Other [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		41,276
Fair Value [Member] | Consumer and Other [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	26,561
Fair Value [Member] | Purchased Credit-Impaired [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				12,218
Fair Value [Member] | Purchased Credit-Impaired [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			7,827
Fair Value [Member] | Allowance for loan losses on PCI loans [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		8,232
Fair Value [Member] | Allowance for loan losses on PCI loans [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		36,031
Fair Value [Member] | Allowance for loan losses on PCI loans [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	11,432
Carrying value [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				463,564
Carrying value [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			577,719
Carrying value [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		706,979
Carrying value [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		1,366,473
Carrying value [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	1,164,790
Carrying value [Member] | Residential Real Estate [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				37,206
Carrying value [Member] | Residential Real Estate [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			142,881
Carrying value [Member] | Residential Real Estate [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		148,342
Carrying value [Member] | Residential Real Estate [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		370,611
Carrying value [Member] | Residential Real Estate [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	284,505
Carrying value [Member] | Commercial Real Estate [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				262,612
Carrying value [Member] | Commercial Real Estate [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			321,262
Carrying value [Member] | Commercial Real Estate [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		375,377
Carrying value [Member] | Commercial Real Estate [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		636,517
Carrying value [Member] | Commercial Real Estate [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	567,506
Carrying value [Member] | Land, Development, Construction [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				47,675
Carrying value [Member] | Land, Development, Construction [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			47,727
Carrying value [Member] | Land, Development, Construction [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		58,530
Carrying value [Member] | Land, Development, Construction [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		149,547
Carrying value [Member] | Land, Development, Construction [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	181,128
Carrying value [Member] | Commercial and Industrial [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				96,587
Carrying value [Member] | Commercial and Industrial [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			46,953
Carrying value [Member] | Commercial and Industrial [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		104,811
Carrying value [Member] | Commercial and Industrial [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		113,818
Carrying value [Member] | Commercial and Industrial [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	88,308
Carrying value [Member] | Consumer and Other [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				2,954
Carrying value [Member] | Consumer and Other [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			7,803
Carrying value [Member] | Consumer and Other [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		1,770
Carrying value [Member] | Consumer and Other [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		41,660
Carrying value [Member] | Consumer and Other [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	26,221
Carrying value [Member] | Purchased Credit-Impaired [Member] | Platinum Bank Holding Company [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans				$ 16,530
Carrying value [Member] | Purchased Credit-Impaired [Member] | Gateway Financial Holdings Of Florida Inc [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans			$ 11,093
Carrying value [Member] | Allowance for loan losses on PCI loans [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		18,149
Carrying value [Member] | Allowance for loan losses on PCI loans [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		$ 54,320
Carrying value [Member] | Allowance for loan losses on PCI loans [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	$ 17,122

Business Combinations - Summa_6

Business Combinations - Summary of Fair Value of Assets Purchased, Including Goodwill and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 01, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets:
Goodwill	$ 802,880			$ 257,683	$ 106,028	$ 76,739
Sunshine Bancorp, Inc. [Member]
Assets:
Cash and cash equivalents			$ 47,056
Loans, held for investment			676,090
Purchased credit impaired loans			8,232
Loans held for sale			430
Investments			93,006
Accrued interest receivable			2,170
Branch real estate			9,375
Furniture and fixtures			916
Bank property held for sale			9,503
FHLB stock			4,875
Bank owned life insurance			23,101
Core deposit intangible			8,525
Goodwill			114,228
Deferred tax asset			11,890
Other assets			5,915
Total assets acquired			1,015,312
Liabilities:
Deposits			719,039
Federal Home Loan Bank advances			95,001
Securities sold under agreement to repurchase			353
Subordinated notes			11,000
Accrued interest payable			457
Other liabilities			1,610
Total liabilities assumed			827,460
HCBF Holding Company, Inc. [Member]
Assets:
Cash and cash equivalents			77,176
Loans, held for investment			1,290,004
Purchased credit impaired loans			36,031
Loans held for sale			5,694
Investments			585,297
Accrued interest receivable			5,847
Branch real estate			34,035
Furniture and fixtures			3,571
Bank property held for sale			14,140
Bank owned life insurance			39,089
Core deposit intangible			23,625
Goodwill			233,321
Deferred tax asset			14,684
Other assets			1,923
Total assets acquired			2,379,069
FHLB and other stock			9,488
Other repossessed real estate owned			5,144
Liabilities:
Deposits			1,755,155
Federal Home Loan Bank advances			157,919
Accrued interest payable			478
Other liabilities			11,409
Total liabilities assumed			1,930,833
Corporate debentures			$ 5,872
Charter Financial Corporation [Member]
Assets:
Cash and cash equivalents		$ 184,020
Loans, held for investment		1,130,240
Purchased credit impaired loans		11,432
Loans held for sale		2,835
Investments		73,808
Accrued interest receivable		3,684
Branch real estate		27,930
Furniture and fixtures		1,988
Bank property held for sale		1,695
Bank owned life insurance		54,813
Core deposit intangible		19,795
Goodwill		197,648
Deferred tax asset		3,441
Other assets		17,644
Total assets acquired		1,734,541
FHLB and other stock		1,483
Other repossessed real estate owned		257
Servicing asset intangible		1,828
Liabilities:
Deposits		1,321,970
Accrued interest payable		1,015
Other liabilities		13,080
Total liabilities assumed		1,345,065
Corporate debentures		$ 9,000

Business Combinations - Pro-For

Business Combinations - Pro-Forma Financial Information And Actual Results of Acquisition (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Combinations [Abstract]
Net interest income	$ 450,847	$ 421,556
Net income available to common shareholders	$ 178,746	$ 96,633
EPS - basic	$ 1.88	$ 1.04
EPS - diluted	$ 1.85	$ 1.02

Interest Rate Swap Derivative_2

Interest Rate Swap Derivatives - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments Notional And Fair Value [Line Items]
Market value of securities pledged	$ 64,706	$ 59,682
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments Notional And Fair Value [Line Items]
Derivative, Notional Amount	5,743,283	3,740,430
Market value of securities pledged		19,048
Collateral reserve for derivatives	$ 28,345	$ 16,991

Interest Rate Swap Derivative_3

Interest Rate Swap Derivatives - Summary Information about the Interest Rate Swap Derivative Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Fair value of interest rate swap derivatives (asset)	$ 92,475	$ 42,480
Fair value of interest rate swap derivatives (liability)	92,892	43,259
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional amount	$ 5,743,283	$ 3,740,430
Weighted average pay rate on interest-rate swaps	3.64%	3.00%
Weighted average receive rate on interest rate swaps	3.64%	3.00%
Weighted average maturity (years)	11 years	11 years
Fair value of interest rate swap derivatives (asset)	$ 92,475	$ 42,480
Fair value of interest rate swap derivatives (liability)	$ 92,892	$ 43,259

Revenue from Contracts with C_2

Revenue from Contracts with Customers - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 293,777	$ 173,248
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | ASU 2014-09 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 0
Revenue, performance obligation, description	There are no minimum orders or future performance obligations or deferred recognition requirements.
Contract revenues	$ 0

Capital Raise - Additional Info

Capital Raise - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 13, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Capital Raise [Abstract]
Proceeds From Public Offering	$ 63,791
Common Stock Issued In Public Offering Shares	2,695,000
Underwriters Over Allotment In Public Offering Shares	245,000
Net Proceeds From Public Offering	$ 63,262	$ 0	$ 63,262	$ 0