CenterState Bank (CSFL) 10-Q 2 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Entity Registrant Name	CenterState Bank Corporation
Trading Symbol	CSFL
Entity Central Index Key	0001102266
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		130,602,499

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks	$ 165,572	$ 107,007
Deposits in other financial institutions (restricted cash)	91,008	28,345
Federal funds sold and FRB deposits	339,223	231,981
Cash and cash equivalents	595,803	367,333
Trading securities, at fair value		1,737
Available for sale debt securities, at fair value	1,701,396	1,727,348
Held to maturity debt securities (fair value of $215,173 and $212,179 at March 31, 2019 and December 31, 2018, respectively)	214,240	216,833
Loans held for sale (see Note 6)	49,474	40,399
Loans, excluding purchased credit impaired	8,199,939	8,181,533
Purchased credit impaired loans	149,456	158,971
Allowance for loan losses	(40,052)	(39,770)
Net Loans	8,309,343	8,300,734
Bank premises and equipment, net	227,182	227,454
Right-of-use lease assets	21,443
Accrued interest receivable	35,336	33,143
FHLB, FRB and other stock, at cost	73,475	79,584
Goodwill	802,880	802,880
Core deposit intangible, net	63,511	66,225
Other intangible assets, net	2,996	2,953
Bank owned life insurance	269,144	267,820
Other repossessed real estate owned	5,981	2,909
Deferred income tax asset, net	38,030	51,462
Bank property held for sale	19,483	25,080
Interest rate swap derivatives, at fair value	130,122	92,475
Prepaid expense and other assets	27,798	31,219
TOTAL ASSETS	12,587,637	12,337,588
Deposits:
Demand - non-interest bearing	3,152,251	2,923,640
Demand - interest bearing	1,813,028	1,811,006
Savings and money market accounts	2,860,616	2,920,730
Time deposits	1,921,130	1,821,960
Total deposits	9,747,025	9,477,336
Securities sold under agreement to repurchase	59,031	57,772
Federal funds purchased	303,017	294,360
Other borrowed funds	211,000	361,000
Corporate debentures	32,503	32,415
Accrued interest payable	3,224	2,627
Interest rate swap derivatives, at fair value	130,790	92,892
Operating and finance lease liabilities	26,050
Payables and accrued expenses	47,445	47,842
Total liabilities	10,560,085	10,366,244
Stockholders' equity:
Common stock, $.01 par value: 200,000,000 shares authorized; 95,913,307 and 95,679,596 shares issued and outstanding at March 31,2019 and December 31, 2018, respectively	959	957
Additional paid-in capital	1,701,047	1,699,031
Retained earnings	326,409	293,777
Accumulated other comprehensive loss	(863)	(22,421)
Total stockholders' equity	2,027,552	1,971,344
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 12,587,637	$ 12,337,588

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Held-to-maturity securities, fair value	$ 215,175	$ 212,179
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	95,913,307	95,679,596
Common stock, shares outstanding	95,913,307	95,679,596

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Interest income:
Loans		$ 116,285	$ 89,930
Investment securities:
Taxable		12,286	10,419
Tax-exempt		1,716	1,557
Federal funds sold and other		1,995	1,253
Total interest income		132,282	103,159
Interest expense:
Deposits		13,323	5,136
Securities sold under agreement to repurchase		236	122
Federal funds purchased and other borrowings		3,978	2,419
Corporate debentures		570	464
Total interest expense		18,107	8,141
Net interest income		114,175	95,018
Provision for loan losses		1,053	1,300
Net interest income after loan loss provision		113,122	93,718
Non-interest income:
Correspondent banking capital markets revenue		7,972	6,890
Other correspondent banking related revenue		1,028	1,233
Small business administration loans revenue		688	988
Debit, prepaid, ATM and merchant card related fees		5,018	3,727
Wealth management related revenue		607	616
Bank owned life insurance income		1,626	1,394
Net gain (loss) on sale of available for sale debt securities		17	(22)
Other non-interest income		1,473	776
Total other income		29,300	23,038
Non-interest expense:
Salaries, wages and employee benefits		48,393	41,893
Occupancy expense		5,602	4,868
Depreciation of premises and equipment		2,850	2,275
Supplies, stationary and printing		748	536
Marketing expenses		2,020	1,414
Data processing expense		3,656	4,505
Legal, audit and other professional fees		1,442	931
Amortization of intangibles		2,814	2,309
Postage and delivery		925	688
ATM and debit card and merchant card related expenses		1,453	764
Bank regulatory expenses		1,616	1,010
Loss (gain) on sale of repossessed real estate (“OREO”)		47	(154)
Valuation write down of repossessed real estate (“OREO”)		108	187
Loss on repossessed assets other than real estate		13	25
Foreclosure related expenses		561	559
Merger related expenses		6,365	8,709
Impairment on bank property held for sale		107	1,449
Other expenses		5,753	4,028
Total other expenses		84,473	75,996
Income before provision for income taxes		57,949	40,760
Provision for income taxes		13,306	5,124
Net income		44,643	35,636
Other comprehensive gain (loss) income, net of tax:
Unrealized available for sale debt securities holding gain (loss), net of income taxes of $7,323, and ($6,280), respectively.		21,571	(18,499)
Less: reclassified adjustments for gain (loss) included in net income, net of income tax expense (benefit) of $4 and ($6), respectively		(13)	16
Net unrealized gain (loss) on available for sale debt securities,net of income taxes		21,558	(18,483)
Total comprehensive income		$ 66,201	$ 17,153
Earnings per share:
Basic		$ 0.47	$ 0.43
Diluted		$ 0.46	$ 0.42
Common shares used in the calculation of earnings per share:
Basic	[1]	95,740,856	83,139,741
Diluted	[1]	96,500,740	84,600,924
Mortgage Banking Revenue
Non-interest income:
Non interest income		$ 4,193	$ 2,602
Service Charges on Deposit Accounts
Non-interest income:
Non interest income		$ 6,678	$ 4,834
[1]	Excludes participating shares.

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Unrealized available for sale debt securities holding gain (loss), income taxes	$ 7,322	$ 6,281
Reclassifications of gain (loss) included in net income, income taxes	$ 4	$ (6)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (unaudited) - USD ($) $ in Thousands	Total	Sunshine Bancorp, Inc. [Member]	HCBF Holding Company, Inc. [Member]	Common Stock [Member]	Common Stock [Member]Sunshine Bancorp, Inc. [Member]	Common Stock [Member]HCBF Holding Company, Inc. [Member]	Additional Paid in Capital [Member]	Additional Paid in Capital [Member]Sunshine Bancorp, Inc. [Member]	Additional Paid in Capital [Member]HCBF Holding Company, Inc. [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balances at beginning at Dec. 31, 2017	$ 904,750			$ 602			$ 737,905			$ 173,248	$ (7,005)
Balances at beginning, shares at Dec. 31, 2017				60,161,334
Net income	35,636									35,636
Unrealized holding gain (loss) on available for sale securities, net of deferred income tax	(18,483)										(18,483)
Dividends paid - common	(8,373)									(8,373)
Stock grants issued				$ 2			(2)
Stock grants issued, shares				184,568
Stock based compensation expense	991						991
Stock options exercised	11,156			$ 13			11,143
Stock options exercised, Shares				1,346,692
Stock repurchase	(980)			$ (1)			(979)
Stock repurchase, shares				(36,928)
Stock issued pursuant to Sunshine acquisition		$ 181,413	$ 387,279		$ 70	$ 151		$ 181,343	$ 387,128
Stock issued pursuant to acquisition, shares					7,050,645	15,051,639
Stock options acquired and convertedpursuant to Sunshine acquisition	18,025	$ 6,432					18,025	$ 6,432
Balances at ending at Mar. 31, 2018	1,517,846			$ 837			1,341,986			200,511	(25,488)
Balances at ending, shares at Mar. 31, 2018				83,757,950
Balances at beginning at Dec. 31, 2018	$ 1,971,344			$ 957			1,699,031			293,777	(22,421)
Balances at beginning, shares at Dec. 31, 2018	95,679,596			95,679,596
Net income	$ 44,643									44,643
Unrealized holding gain (loss) on available for sale securities, net of deferred income tax	21,558										21,558
Cumulative adjustment pursuant to adoption of ASU 842	(1,464)									(1,464)
Dividends paid - common	(10,547)									(10,547)
Stock grants issued				$ 1			(1)
Stock grants issued, shares				132,918
Stock based compensation expense	1,218						1,218
Stock options exercised	1,199			$ 1			1,198
Stock options exercised, Shares				116,764
Stock repurchase	(399)						(399)
Stock repurchase, shares				(15,971)
Balances at ending at Mar. 31, 2019	$ 2,027,552			$ 959			$ 1,701,047			$ 326,409	$ (863)
Balances at ending, shares at Mar. 31, 2019	95,913,307			95,913,307

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Member]
Unrealized holding gain on available for sale securities, deferred income tax	$ 7,318	$ 6,275
Retained Earnings [Member]
Dividends paid - common, per share	$ 0.11	$ 0.10

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income	$ 44,643	$ 35,636
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	1,053	1,300
Depreciation of premises and equipment	2,850	2,275
Accretion of purchase accounting adjustments	(12,982)	(11,815)
Net amortization of investment securities	2,421	3,169
Net deferred loan origination fees	344	1
(Gain) loss on sale of securities available for sale debt securities	(17)	22
Trading securities revenue	(25)	0
Purchases of trading securities	(51,691)	(46,940)
Proceeds from sale of trading securities	53,453	53,289
Repossessed real estate owned valuation write down	108	187
Loss (gain) on sale of repossessed real estate (“OREO”)	47	(154)
Loss on repossessed assets other than real estate	13	25
Gain on sale of residential loans held for sale	(3,976)	(1,574)
Residential loans originated and held for sale	(134,752)	(58,098)
Proceeds from sale of residential loans held for sale	129,657	57,321
Net change in fair value of residential loans held for sale	(4)	(363)
Gain on disposal of and or sale of fixed assets	(1)	(3)
Gain on disposal of bank property held for sale	(618)	(159)
Impairment on bank property held for sale	107	1,449
Gain on sale of small business administration loans	(688)	(988)
Small business administration loans originated for sale	(7,482)	(10,140)
Proceeds from sale of small business administration loans	8,170	11,128
Deferred income taxes	6,114	7,760
Tax deduction in excess of book deduction for stock awards	(376)	(4,539)
Stock based compensation expense	1,218	991
Bank owned life insurance income	(1,626)	(1,394)
Net cash from changes in:
Net changes in accrued interest receivable, prepaid expenses, and other assets	11,461	47,518
Net change in accrued interest payable, accrued expense, and other liabilities	(5,019)	(29,430)
Net cash provided by operating activities	42,402	56,474
Cash flows from investing activities:
Purchases of investment securities	(1,037)	(23,944)
Purchases of mortgage backed securities	(66,624)	(196,692)
Proceeds from pay-downs of mortgage backed securities	53,579	44,755
Proceeds from sales of investment securities	2,309	58,768
Proceeds from sales of mortgage backed securities	64,177	296,884
Proceeds from called investment securities		540
Proceeds from maturities of investment securities	295	0
Proceeds from pay-downs of mortgage backed securities	2,317	4,081
Purchases of FHLB and FRB stock	(4,717)	(12,723)
Proceeds from sales of FHLB and FRB stock	10,826	18,819
Net increase in loans	1,956	(81,160)
Purchases of premises and equipment, net	(3,931)	(4,168)
Proceeds from sale of repossessed real estate	430	3,581
Proceeds from sale of fixed assets	1	3
Proceeds from sale of bank property held for sale	6,365	2,403
Net cash from bank acquisitions		81,293
Net cash provided by investing activities	65,946	192,440
Cash flows from financing activities:
Net increase in deposits	269,954	77,873
Net increase (decrease) in securities sold under agreement to repurchase	1,259	(2,831)
Net increase (decrease) in federal funds purchased	8,657	(45,838)
Net decrease in other borrowings	(150,000)	(157,920)
Net decrease in payable to shareholders for acquisitions	(1)	(1)
Stock options exercised	1,199	11,156
Stock repurchased	(399)	(980)
Dividends paid	(10,547)	(8,373)
Net cash (used in) provided by financing activities	120,122	(126,914)
Net increase in cash and cash equivalents	228,470	122,000
Cash and cash equivalents, beginning of period	367,333	280,619
Cash and cash equivalents, end of period	595,803	402,619
Supplemental Information
Transfer of loans to other real estate owned	3,657	1,297
Transfers of bank property to held for sale		1,410
Initial recognition of operating right-of-use assets	20,311
Initial recognition of operating lease liabilities	22,795
Cash paid during the period for:
Interest	$ 17,689	$ 8,640

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Nature of Operations and Basis of Presentation	NOTE 1: Nature of operations and basis of presentation The consolidated financial statements include the accounts of CenterState Bank Corporation (the “Parent Company,” “Company” or “CSFL”), and its wholly owned subsidiary bank, CenterState Bank, N.A. (“CenterState” or “Bank”), and non-bank subsidiaries, R4ALL, Inc. and CSFL Insurance Corp. The Company operates as one of the largest community bank franchises headquartered in the state of Florida. The Bank provides traditional retail, commercial, mortgage, wealth management and SBA services throughout its Florida, Georgia and Alabama branch network and customer relationships in neighboring states. The Bank, headquartered in Winter Haven, Florida, also operates a correspondent banking and capital markets division, of which the majority of its bond salesmen, traders and operational personnel are primarily housed in facilities located in Birmingham, Alabama and Atlanta, Georgia. This division’s primary revenue generating activities are related to its capital markets division, which includes commissions earned on fixed income security sales, fees from hedging services, loan brokerage fees and consulting fees for services related to these activities; and its correspondent banking division, which includes spread income earned on correspondent bank deposits (i.e. federal funds purchased) and correspondent bank checking account deposits and fees from safe-keeping activities, bond accounting services for correspondents, asset/liability consulting related activities, international wires, and other clearing and corporate checking account services. The customer base includes small to medium size financial institutions primarily located in the Southeastern United States, although clients are located across the United States. R4ALL, Inc. manages troubled loans purchased from the Bank to their eventual disposition. CSFL Insurance Corp. is a captive insurance subsidiary pursuant to Section 831(b) of the U.S. Tax Code. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial statements and with the instructions to Form 10-Q. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States of America for complete financial statements. These statements should be read in conjunction with the consolidated financial statements included in the Annual Report on Form 10-K for the year ended December 31, 2018. In the Company’s opinion, all adjustments, consisting primarily of normal recurring adjustments, necessary for a fair presentation of the results for the interim periods have been made. The results of operations of the three-month period ended March 31, 2019 are not necessarily indicative of the results expected for the full year. Some items in the prior period financial statements were reclassified to conform to the current presentation. Reclassifications had no effect on prior period net income or shareholders’ equity.

Common Stock Outstanding and Ea

Common Stock Outstanding and Earnings Per Share Data	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Common Stock Outstanding and Earnings Per Share Data	NOTE 2: Common stock outstanding and earnings per share data 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 Three months ended March 31, 2019 2018 Basic Net income available to common shareholders $ 44,643 $ 35,636 Less: Earnings allocated to participating securities (23 ) (29 ) Net income allocated to common shareholders $ 44,620 $ 35,607 Weighted average common shares outstanding including participating securities 95,790,456 83,208,874 Less: Participating securities (1) (49,600 ) (69,133 ) Average shares 95,740,856 83,139,741 Basic earnings per common share $ 0.47 $ 0.43 Diluted Net income available to common shareholders $ 44,620 $ 35,607 Weighted average common shares outstanding for basic earnings per common share 95,740,856 83,139,741 Add: Dilutive effects of stock based compensation awards 759,884 1,461,183 Average shares and dilutive potential common shares 96,500,740 84,600,924 Diluted earnings per common share $ 0.46 $ 0.42 (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.

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value	NOTE 3: 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. 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. 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 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 March 31 2019, the range of capitalization rates utilized to determine the fair value of the underlying collateral ranged from 4% to 12%. Adjustments to appraisals 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, other real estate owned and bank property held for sale 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 Quoted prices Significant in active other Significant markets for observable unobservable Carrying identical assets inputs inputs value (Level 1) (Level 2) (Level 3) at March 31, 2019 Assets: Available for sale debt securities Corporate debt securities $ 5,094 — $ 5,094 — Obligations of U.S. government sponsored entities and agencies 36,356 — 36,356 — Mortgage backed securities 1,569,253 — 1,569,253 — Municipal securities 90,693 — 90,693 — Loans held for sale, at fair value 49,474 — 49,474 — Mortgage servicing assets 1,532 — 1,532 — Mortgage banking derivatives 1,512 — 4 1,508 Interest rate swap derivatives 130,122 — 130,122 — Liabilities: Mortgage banking derivatives 341 — 335 6 Interest rate swap derivatives 130,790 — 130,790 — 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 — 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 March 31, 2019 Assets: Impaired loans Residential real estate $ 1,518 — — $ 1,518 Commercial real estate 7,294 — — 7,294 Land, land development and construction 91 — — 91 Commercial 2,364 — — 2,364 Consumer 31 — — 31 Other real estate owned Residential real estate 32 — — 32 Commercial real estate — — — — Land, land development and construction 813 — — 813 Bank property held for sale 4,635 — — 4,635 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 Residential real estate — — — — Commercial real estate — — — — Land, land development and construction 867 — — 867 Bank property held for sale 5,805 — — 5,805 Impaired loans measured at fair value had a recorded investment of $11,298 with a valuation allowance of $2,355 at March 31, 2019, and a recorded investment of $8,829, with a valuation allowance of $1,463 at December 31, 2018. The Company recorded a provision for loan loss expense of $1,124 and $68 impaired loans carried at fair value during three-month periods ending March 31, 2019 and 2018, respectively. Other real estate owned had a decline in fair value of $108 and $187 during the three-month periods ending March 31, 2019 and 2018, respectively. Changes in fair value were recorded directly 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. 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. 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 Short-term 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 March 31, 2019 Carrying amount Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents $ 595,803 $ 595,803 $ — $ — $ 595,803 Available for sale debt securities 1,701,396 — 1,701,396 — 1,701,396 Held to maturity debt securities 214,240 — 215,175 — 215,175 Loans held for sale, at fair value 49,474 — 49,474 — 49,474 Loans, net 8,309,343 — — 8,355,012 8,355,012 Mortgage servicing assets 1,532 — 1,532 — 1,532 Mortgage banking derivatives 1,512 — 4 1,508 1,512 Interest rate swap derivatives 130,122 — 130,122 — 130,122 Accrued interest receivable 35,336 — 8,069 27,267 35,336 Financial liabilities: Deposits- without stated maturities $ 7,825,895 $ 7,825,895 $ — $ — $ 7,825,895 Deposits- with stated maturities 1,921,130 — 1,924,046 — 1,924,046 Securities sold under agreement to repurchase 59,031 — 59,031 — 59,031 Federal funds purchased and other borrowings 514,017 — 514,017 — 514,017 Corporate debentures 32,503 — — 28,562 28,562 Mortgage banking derivatives 341 — 335 6 341 Interest rate swap derivatives 130,790 — 130,790 — 130,790 Accrued interest payable 3,224 — 3,224 — 3,224 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 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

Reportable Segments

Reportable Segments	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Reportable Segments	NOTE 4: 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 table below is a reconciliation of the reportable segment revenues, expenses, and profit to the Company’s consolidated total for the three-month periods ending March 31, 2019 and 2018. Three-month period ending March 31, 2019 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 127,832 $ 4,450 $ — $ — $ 132,282 Interest expense (14,851 ) (2,549 ) (707 ) — (18,107 ) Net interest income (expense) 112,981 1,901 (707 ) — 114,175 Provision for loan losses (1,015 ) (38 ) — — (1,053 ) Non-interest income 20,300 9,000 — — 29,300 Non-interest expense (77,581 ) (5,713 ) (1,179 ) — (84,473 ) Net income (loss) before taxes 54,685 5,150 (1,886 ) — 57,949 Income tax (provision) benefit (12,690 ) (1,305 ) 689 — (13,306 ) Net income $ 41,995 $ 3,845 $ (1,197 ) $ — $ 44,643 Total assets $ 11,939,930 $ 647,046 $ 2,073,703 $ (2,073,042 ) $ 12,587,637 Three-month period ending March 31, 2018 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 100,969 $ 2,190 $ — $ — $ 103,159 Interest expense (6,207 ) (1,072 ) (862 ) — (8,141 ) Net interest income (expense) 94,762 1,118 (862 ) — 95,018 Provision for loan losses (1,162 ) (138 ) — — (1,300 ) Non-interest income 14,915 8,123 — — 23,038 Non-interest expense (69,997 ) (5,610 ) (389 ) — (75,996 ) Net income (loss) before taxes 38,518 3,493 (1,251 ) — 40,760 Income tax (provision) benefit (8,499 ) (885 ) 4,260 — (5,124 ) Net income $ 30,019 $ 2,608 $ 3,009 $ — $ 35,636 Total assets $ 9,843,219 $ 499,678 $ 1,585,585 $ (1,580,486 ) $ 10,347,996 Commercial and retail banking Correspondent banking and capital markets division Corporate overhead and administration

Investment securities

Investment securities	3 Months Ended
	Mar. 31, 2019
Investments Debt And Equity Securities [Abstract]
Investment securities	NOTE 5: Investment securities Available for Sale Debt Securities All of the mortgage-backed securities (“MBS”) listed below are residential Fannie Mae, Freddie Mac and Ginnie Mae MBSs . The fair value of available for sale debt securities and the related gross unrealized gains and losses recognized in accumulated other comprehensive income (loss) were as follows: March 31, 2019 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value Corporate debt securities $ 5,000 $ 94 $ — $ 5,094 Obligations of U.S. government sponsored entities and agencies 36,894 6 544 36,356 Mortgage-backed securities 1,572,732 8,939 12,418 1,569,253 Municipal securities 87,927 2,766 — 90,693 Total available for sale debt securities $ 1,702,553 $ 11,805 $ 12,962 $ 1,701,396 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 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 Bancorp, Inc. (“Sunshine”) and HCBF Holding Company, Inc. (“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 debt securities for the three months ended March 31, 2019 and 2018 were as follows: For the three months ended: March 31, 2019 March 31, 2018 Proceeds $ 66,486 $ 355,652 Gross gains 646 68 Gross losses 629 90 The tax provision related to these net realized gain and loss were $4 and ($6), respectively. The fair value of available for sale debt securities at March 31, 2019 by contractual maturity were as follows. Securities not due at a single maturity date, primarily mortgage-backed securities, are shown separately. Fair Amortized Available for sale debt securities: Value Cost Due one year or less $ 661 $ 661 Due after one year through five years 6,911 6,851 Due after five years through ten years 29,959 29,793 Due after ten years through thirty years 94,612 92,516 Mortgage-backed securities 1,569,253 1,572,732 Total available for sale debt securities $ 1,701,396 $ 1,702,553 Available for sale debt securities pledged at March 31, 2019 and December 31, 2018 had a carrying amount (estimated fair value) of $879,638 and $961,721 respectively. These securities were pledged primarily to increase borrowing capacity at the FHLB, secure public deposits and repurchase agreements. At March 31, 2019 and December 31, 2018, there were no holdings of securities of any one issuer, other than mortgage-backed securities issued by U.S. Government sponsored entities, in an amount greater than 10% of stockholders’ equity. The following tables show the Company’s available for sale debt investments’ gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at March 31, 2019 and December 31, 2018. March 31, 2019 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses Obligations of U.S. government sponsored entities and agencies $ 18,135 $ 220 $ 16,323 $ 324 $ 34,458 $ 544 Mortgage backed securities 947 10 990,146 12,408 991,093 12,418 Total temporarily impaired available for sale debt securities $ 19,082 $ 230 $ 1,006,469 $ 12,732 $ 1,025,551 $ 12,962 December 31, 2018 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses 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 Obligations of U.S. government sponsored entities and agencies: Obligations of U.S. government-sponsored entities and agencies are mainly comprised of pools of securities issued by the Small Business Administration (“SBA”). 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 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 March 31, 2019. Mortgage-backed securities: At March 31, 2019, 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 March 31, 2019. 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 March 31, 2019 and December 31, 2018. March 31, 2019 Gross Gross Amortized Unrecognized Unrecognized Fair Cost Gains Losses Value Mortgage-backed securities $ 82,517 $ — $ 1,269 $ 81,248 Municipal securities 131,723 2,393 189 133,927 Total held to maturity debt securities $ 214,240 $ 2,393 $ 1,458 $ 215,175 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 Held to maturity securities pledged at March 31, 2019 and December 31, 2018 had a carrying amount of $103,504 and $103,710 respectively. These securities were pledged primarily to secure public deposits and repurchase agreements. At March 31, 2019, 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 stockholders’ equity. The fair value and amortized cost of held to maturity securities at March 31, 2019 by contractual maturity were as follows. Mortgage-backed securities are not due at a single maturity date and are shown separately. Fair Amortized Held to maturity debt securities Value Cost Due after five years through ten years $ 2,064 $ 2,041 Due after ten years through thirty years 131,863 129,682 Mortgage-backed securities 81,248 82,517 Total held to maturity debt securities $ 215,175 $ 214,240 The following table shows 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 March 31, 2019 and December 31, 2018. March 31, 2019 Less than 12 months 12 months or more Total Fair Unrecognized Fair Unrecognized Fair Unrecognized Value Losses Value Losses Value Losses Mortgage backed securities $ — $ — $ 81,248 $ 1,269 $ 81,248 $ 1,269 Municipal securities — — 19,637 189 19,637 189 Total temporarily impaired held to maturity debt securities $ — $ — $ 100,885 $ 1,458 $ 100,885 $ 1,458 December 31, 2018 Less than 12 months 12 months or more Total Fair Unrecognized Fair Unrecognized Fair Unrecognized Value Losses Value Losses 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 Mortgage-backed securities: At March 31, 2019, 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 March 31, 2019. 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.

Loans Held for Sale

Loans Held for Sale	3 Months Ended
	Mar. 31, 2019
Loans Receivable Held For Sale Net [Abstract]
Loans Held for Sale	NOTE 6: Loans Held for Sale 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 $4 at March 31, 2019. The total unpaid principal balance of loans held for sale was $49,470 The table below summarizes the activity in mortgage loans held for sale during the three-month periods ending March 31, 2019 and 2018. Three-month periods ended Mar. 31, 2019 Mar. 31, 2018 Beginning balance $ 40,399 $ 19,647 Effect from acquisitions — 6,124 Loans originated 134,752 58,098 Proceeds from sales (129,657 ) (57,321 ) Net change in fair value 4 363 Net realized gain on sales 3,976 1,574 Ending balance $ 49,474 $ 28,485 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 uses these derivative financial instruments on its loans held for sale to manage interest rate risk and not for speculative purposes. The net realized gain on sales of loans held for sale of $3,976, the mortgage servicing fee of $93, and the net unrealized gain on mortgage banking derivatives of $557, the change in fair value of $4, mortgage hedge loss of $404, and mortgage servicing asset loss of $33 are the components of Mortgage Banking Revenue as of March 31, 2019. The net realized gain on sales of loans held for sale of $1,574, the net unrealized gain on mortgage banking derivatives of $665, and the change in fair value of $363 are the main components of Mortgage Banking Revenue as of March 31, 2018. The Mortgage Banking Revenue amounts are 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 March 31, 2019 and 2018. Notional at March 31, 2019 March 31, 2018 Interest rate lock commitments $ 85,802 $ 45,488 Best efforts forward trades 92,115 62,426 MBS forward trades 57,000 — Total derivative instruments $ 234,917 $ 107,914 Mortgage banking derivatives 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	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Loans	NOTE 7: Loans The following table sets forth information concerning the loan portfolio by collateral types as of the dates indicated. March 31, 2019 December 31, 2018 Loans excluding PCI loans Real estate loans Residential $ 1,762,696 $ 1,702,114 Commercial 4,400,583 4,454,098 Land, development and construction 651,112 635,562 Total real estate 6,814,391 6,791,774 Commercial 1,175,966 1,183,380 Consumer and other loans 206,545 203,686 Loans before unearned fees and deferred cost 8,196,902 8,178,840 Net unearned fees and costs 3,037 2,693 Total loans excluding PCI loans 8,199,939 8,181,533 PCI loans (note 1) Real estate loans Residential 55,532 58,804 Commercial 80,792 87,336 Land, development and construction 7,261 7,028 Total real estate 143,585 153,168 Commercial 5,662 5,594 Consumer and other loans 209 209 Total PCI loans 149,456 158,971 Total loans 8,349,395 8,340,504 Allowance for loan losses for loans that are not PCI loans (39,861 ) (39,579 ) Allowance for loan losses for PCI loans (191 ) (191 ) Total loans, net of allowance for loan losses $ 8,309,343 $ 8,300,734 Note 1: Purchased credit impaired (“PCI”) loans are being accounted for pursuant to ASC Topic 310-30. The table below set forth the activity in the allowance for loan losses for the periods presented. Allowance for loan losses for loans that are not PCI loans Allowance for loan losses on PCI loans Total Three months ended March 31, 2019 Balance at beginning of period $ 39,579 $ 191 $ 39,770 Loans charged-off (1,447 ) — (1,447 ) Recoveries of loans previously charged-off 676 — 676 Net charge-offs (771 ) — (771 ) Provision for loan losses 1,053 — 1,053 Balance at end of period $ 39,861 $ 191 $ 40,052 Three months ended March 31, 2018 Balance at beginning of period $ 32,530 $ 295 $ 32,825 Loans charged-off (403 ) — (403 ) Recoveries of loans previously charged-off 632 75 707 Net recoveries 229 75 304 Provision for loan losses 1,395 (95 ) 1,300 Balance at end of period $ 34,154 $ 275 $ 34,429 The following tables present the activity in the allowance for loan losses by portfolio segment for the periods presented. Real Estate Loans Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses for loans that are not PCI loans: Three months ended March 31, 2019 Beginning of the period $ 5,518 $ 22,978 $ 1,781 $ 6,414 $ 2,888 $ 39,579 Charge-offs (201 ) — (31 ) (664 ) (551 ) (1,447 ) Recoveries 142 152 83 155 144 676 Provision for loan losses (11 ) (883 ) 387 1,025 535 1,053 Balance at end of period $ 5,448 $ 22,247 $ 2,220 $ 6,930 $ 3,016 $ 39,861 Three months ended March 31, 2018 Beginning of the period $ 6,003 $ 19,304 $ 1,179 $ 4,130 $ 1,914 $ 32,530 Charge-offs (136 ) — — (7 ) (260 ) (403 ) Recoveries 274 94 — 6 258 632 Provision for loan losses (394 ) 1,577 115 372 (275 ) 1,395 Balance at end of period $ 5,747 $ 20,975 $ 1,294 $ 4,501 $ 1,637 $ 34,154 Real Estate Loans Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses for loans that are PCI loans: Three months ended March 31, 2019 Beginning of the period $ — $ — $ 177 $ — $ 14 $ 191 Charge-offs — — — — — — Recoveries — — — — — — Provision for loan losses — — — — — — Balance at end of period $ — $ — $ 177 $ — $ 14 $ 191 Three months ended March 31, 2018 Beginning of the period $ — $ 59 $ 222 $ — $ 14 $ 295 Charge-offs — — — — — — Recoveries — — 75 — — 75 Provision for loan losses — — (95 ) — — (95 ) Balance at end of period $ — $ 59 $ 202 $ — $ 14 $ 275 The following tables present the balance in the allowance for loan losses and the recorded investment in loans by portfolio segment and based on impairment method as of March 31, 2019 and December 31, 2018. Accrued interest receivable and unearned loan fees and costs are not included in the recorded investment because they are not material. Real Estate Loans As of March 31, 2019 Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 324 $ 761 $ — $ 1,389 $ 1 $ 2,475 Collectively evaluated for impairment 5,124 21,486 2,220 5,541 3,015 37,386 Purchased credit impaired — — 177 — 14 191 Total ending allowance balance $ 5,448 $ 22,247 $ 2,397 $ 6,930 $ 3,030 $ 40,052 Loans: Individually evaluated for impairment $ 5,657 $ 8,078 $ 116 $ 3,492 $ 134 $ 17,477 Collectively evaluated for impairment 1,757,039 4,392,505 650,996 1,172,474 206,411 8,179,425 Purchased credit impaired 55,532 80,792 7,261 5,662 209 149,456 Total ending loan balances $ 1,818,228 $ 4,481,375 $ 658,373 $ 1,181,628 $ 206,754 $ 8,346,358 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 The table below summarizes impaired loan data for the periods presented. Mar. 31, 2019 Dec. 31, 2018 Performing TDRs (these are not included in nonperforming loans ("NPLs")) $ 8,801 $ 8,475 Nonperforming TDRs (these are included in NPLs) 1,092 1,002 Total TDRs (these are included in impaired loans) 9,893 9,477 Impaired loans that are not TDRs 7,584 6,223 Total impaired loans $ 17,477 $ 15,700 Troubled Debt Restructurings: In certain situations, it is common to restructure or modify the terms of troubled loans (i.e. troubled debt restructure or “TDRs”). In those circumstances, it may be beneficial to restructure the terms of a loan and work with the borrower for the benefit of both parties, versus forcing the property into foreclosure and having to dispose of it in a distressed sale. When the terms of a loan have been modified, usually the monthly payment and/or interest rate is reduced for generally twelve to twenty-four months. The Company has not forgiven any material principal amounts on any loan modifications to date. TDRs as of March 31, 2019 and December 31, 2018 quantified by loan type classified separately as accrual (performing loans) and non-accrual (non-performing loans) are presented in the tables below. As of March 31, 2019 Accruing Non-Accrual Total Real estate loans: Residential $ 5,507 $ 489 $ 5,996 Commercial 1,823 563 2,386 Land, development, construction 76 40 116 Total real estate loans 7,406 1,092 8,498 Commercial 1,261 — 1,261 Consumer and other 134 — 134 Total TDRs $ 8,801 $ 1,092 $ 9,893 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 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. Our 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 $31 and partial charge offs of $8 on the TDR loans described above during the three-month period ending March 31, 2019. The Company recorded a provision Loans are modified to minimize loan losses when we believe the modification will improve the borrower’s financial condition and ability to repay the loan. We typically do not forgive principal. We generally either reduce interest rates or decrease monthly payments for a temporary period of time and those reductions of cash flows are capitalized into the loan balance. We 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 we try to accommodate the borrower and minimize the Company’s potential losses. Approximately 89% of our TDRs are current pursuant to their modified terms, and $1,092, or approximately 11% of our 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. One loan with a balance of $713 was modified as a TDR during the three-month period ending March 31, 2019. No loan loss provision was recorded during the three-month period ending March 31, 2019. Loans modified as TDRs during the three-month period ending March 31, 2018 were $1,563. The Company recorded no loan loss provision for loans modified during the three-month period ending March 31, 2018. The following table presents loans by class modified and for which there was a payment default within twelve months following the modification during the periods ending March 31, 2019 and 2018. Period ending Period ending March 31, 2019 March 31, 2018 Number Recorded Number Recorded of loans investment of loans investment Residential — $ — — $ — Commercial real estate — — 1 174 Land, development, construction — — — — Commercial and Industrial 1 122 — — Consumer and other — — — — Total 1 $ 122 1 $ 174 The Company recorded no provision for loan loss expense and no partial charge offs on TDR loans subsequently defaulted during the three-month period ending March 31, 2019. The Company recorded a provision for loan loss expense of $2 and partial charge offs of $2 on TDR loans that subsequently defaulted as described above during the three-month period ending March 31, 2018. The following tables present loans individually evaluated for impairment by class of loans as of March 31, 2019 and December 31, 2018, excluding purchased credit impaired loans accounted for pursuant to ASC Topic 310-30. The recorded investment is less than the unpaid principal balance due to partial charge-offs. As of March 31, 2019 Unpaid principal balance Recorded investment Allowance for loan losses allocated With no related allowance recorded: Residential real estate $ 3,030 $ 2,973 $ — Commercial real estate 5,469 4,799 — Land, development, construction 143 116 — Commercial and industrial 1,056 1,045 — Consumer, other 108 107 — With an allowance recorded: Residential real estate 2,859 2,684 324 Commercial real estate 3,423 3,279 761 Land, development, construction — — — Commercial and industrial 2,481 2,447 1,389 Consumer, other 32 27 1 Total $ 18,601 $ 17,477 $ 2,475 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 Three months ended March 31, 2019 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 5,945 $ 62 $ — Commercial 7,787 25 — Land, development, construction 117 1 — Total real estate loans 13,849 88 — Commercial and industrial 2,600 12 — Consumer and other loans 140 2 — Total $ 16,589 $ 102 $ — Three months ended March 31, 2018 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 8,133 $ 77 $ — Commercial 8,264 12 — Land, development, construction 264 3 — Total real estate loans 16,661 92 — Commercial and industrial 3,025 6 — Consumer and other loans 195 2 — Total $ 19,881 $ 100 $ — Nonperforming loans include both smaller balance homogeneous loans that are collectively evaluated for impairment and individually classified impaired loans, excluding purchased credit impaired loans accounted for pursuant to ASC Topic 310-30. Nonperforming loans were as follows: Mar. 31, 2019 Dec. 31, 2018 Non-accrual loans $ 35,181 $ 23,567 Loans past due over 90 days and still accruing interest — — Total non-performing loans $ 35,181 $ 23,567 The following table presents the recorded investment in nonaccrual loans and loans past due over 90 days still on accrual by class of loans as of March 31, 2019 and December 31, 2018, excluding purchased credit impaired loans: As of March 31, 2019 Nonaccrual Loans past due over 90 days still accruing Residential real estate $ 12,888 $ — Commercial real estate 10,259 — Land, development, construction 6,965 — Commercial 4,425 — Consumer, other 644 — Total $ 35,181 $ — As of December 31, 2018 Nonaccrual 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 $ — The following table presents the aging of the recorded investment in past due loans as of March 31, 2019 and December 31, 2018, excluding purchased credit impaired loans: 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 Nonaccrual Loans As of March 31, 2019 Residential real estate $ 1,762,696 $ 10,610 $ 3,172 $ — $ 13,782 $ 1,736,026 $ 12,888 Commercial real estate 4,400,583 7,012 4,856 — 11,868 4,378,456 10,259 Land/dev/construction 651,112 4,036 79 — 4,115 640,032 6,965 Commercial 1,175,966 3,532 368 — 3,900 1,167,641 4,425 Consumer 206,545 709 261 — 970 204,931 644 $ 8,196,902 $ 25,899 $ 8,736 $ — $ 34,635 $ 8,127,086 $ 35,181 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 Nonaccrual 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 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 March 31, 2019 and December 31, 2018 , 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. As of March 31, 2019 Loan Category Pass Special Mention Substandard Doubtful Residential real estate $ 1,696,127 $ 38,771 $ 27,798 $ — Commercial real estate 4,210,370 144,831 45,382 — Land/dev/construction 632,862 14,109 4,141 — Commercial 1,127,102 41,986 6,878 — Consumer 205,470 224 851 — Total $ 7,871,931 $ 239,921 $ 85,050 $ — 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 $ — 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, based on payment activity as of March 31, 2019 and December 31, 2018: As of March 31, 2019 Residential Consumer Performing $ 1,749,808 $ 205,901 Nonperforming 12,888 644 Total $ 1,762,696 $ 206,545 As of December 31, 2018 Residential Consumer Performing $ 1,690,626 $ 203,121 Nonperforming 11,488 565 Total $ 1,702,114 $ 203,686 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 March 31, 2019 and December 31, 2018. Contractually required principal and interest payments have been adjusted for estimated prepayments. Mar. 31, 2019 Dec. 31, 2018 Contractually required principal and interest $ 248,243 $ 267,815 Non-accretable difference (28,865 ) (38,602 ) Cash flows expected to be collected 219,378 229,213 Accretable yield (69,922 ) (70,242 ) Carrying value of acquired loans 149,456 158,971 Allowance for loan losses (191 ) (191 ) Carrying value less allowance for loan losses $ 149,265 $ 158,780 total contractually required principal and interest cash payments, management’s estimate of expected total cash payments and carrying value of the loans during the three - month periods ending March 31, 2019 and 2018 . Activity during the Effect of income all other three-month period ending March 31, 2019 Dec. 31, 2018 acquisitions accretion adjustments Mar. 31, 2019 Contractually required principal and interest $ 267,815 $ — $ — $ (19,572 ) $ 248,243 Non-accretable difference (38,602 ) — — 9,737 (28,865 ) Cash flows expected to be collected 229,213 — — (9,835 ) 219,378 Accretable yield (70,242 ) — 10,140 (9,820 ) (69,922 ) Carry value of acquired loans $ 158,971 $ — $ 10,140 $ (19,655 ) $ 149,456 Activity during the Effect of income all other three-month period ending March 31, 2018 Dec. 31, 2017 acquisitions accretion adjustments Mar. 31, 2018 Contractually required principal and interest $ 248,283 $ 88,705 $ — $ (21,711 ) $ 315,277 Non-accretable difference (13,183 ) (38,164 ) — 1,110 (50,237 ) Cash flows expected to be collected 235,100 50,541 — (20,601 ) 265,040 Accretable yield (70,942 ) (6,278 ) 7,718 (2,355 ) (71,857 ) Carry value of acquired loans $ 164,158 $ 44,263 $ 7,718 $ (22,956 ) $ 193,183

Securities Sold Under Agreement

Securities Sold Under Agreement to Repurchase	3 Months Ended
	Mar. 31, 2019
Banking And Thrift [Abstract]
Securities Sold Under Agreement to Repurchase	NOTE 8: Securities sold under agreement to repurchase Our Bank enters into borrowing arrangements with our retail business customers by agreements to repurchase (“securities sold under agreements to repurchase”) under which the bank pledges investment securities owned and under its control as collateral against these one-day borrowing arrangement. These short-term borrowings totaled $ at March 31, 2019 MBS Municipal As of March 31, 2019 Securities Securities Total Market value of securities pledged $ 62,611 $ 442 $ 63,053 Borrowings related to pledged amounts 58,829 202 59,031 Market value pledged as a % of borrowings 106 % 219 % 107 % As of December 31, 2018 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 % Any risk related to these arrangements, primarily market value changes, are minimized due to the overnight (one day) maturity and the additional collateral pledged over the borrowed amounts.

Business Combinations

Business Combinations	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Business Combinations	NOTE 9: Business Combinations 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, 2018, 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 three-month periods ending March 31, 2019 and 2018, the Company incurred approximately $0 and $2,071 of acquisition costs related to this transaction. These acquisition costs are reported in merger and acquisition related expenses on the Company’s Condensed 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 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, 2018, 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, 2018 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, 2018 $ 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 11,670 Other assets 6,135 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, 2018. 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, 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 HCBF Holding Company, Inc. On January 1, 2018, the Company completed its acquisition of HCBF Holding Company, Inc. (“Harbor”) whereby Harbor merged with and into the Company. Pursuant to and simultaneously with the merger of Harbor with and into the Company, Harbor’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, 2018, 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 three-month periods ending March 31, 2019 and 2018, the Company incurred approximately $0 and $5,789 of acquisition costs related to this transaction. These acquisition costs are reported in merger and acquisition 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 Harbor. The purchase price consisted of both cash and stock. Each share of Harbor 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, 2018, the resulting purchase price was $448,236. The table below summarizes the purchase price calculation. Number of shares of Harbor common stock outstanding at December 31, 2018 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, 2018 $ 25.73 Fair value of CenterState common stock issued $ 387,279 Number of shares of Harbor common stock outstanding at December 31, 2018 22,299,082 Cash consideration each Harbor 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 Harbor common shareholders $ 430,211 Fair value of Harbor stock options converted to CenterState stock options $ 18,025 Total Purchase Price for Harbor $ 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 14,071 Other assets 2,536 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, 2018. 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, 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 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% as compared with the balances at December 31, 2018, 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 three-month period ending March 31, 2019, the Company incurred approximately $5,102 of acquisition costs related to this transaction. These acquisition costs are reported in merger and acquisition 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 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, 2018. 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, 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. Pro-forma information Pro-forma data for the three-month period ending March 31, 2018 listed in the table below presents pro-forma information as if the Charter acquisitions occurred at the beginning of 2018. Three months ended March 31, 2018 Net interest income $ 112,182 Net income available to common shareholders $ 51,250 EPS - basic $ 0.54 EPS - diluted $ 0.53 The disclosures regarding the results of operations Charter subsequent to its respective acquisition date is omitted as this information is not practical to obtain. Although the Company did not convert Charter’s core system until the first quarter of 2019, the majority of the fixed costs and purchase accounting entries were booked on the Company’s core system making it impractical to determine Charter’s results of operation on a stand-alone basis.

Interest Rate Swap Derivatives

Interest Rate Swap Derivatives	3 Months Ended
	Mar. 31, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Interest Rate Swap Derivatives	NOTE 10: 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 March 31, 2019 and December 31, 2018, the notional amount of such arrangements were $6,194,936 $91,008 and $28,345 of cash as collateral to the third party dealers at March 31, 2019 and December 31, 2018 , respectively . 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 interest rate swap derivative instruments is as follows: Mar. 31, 2019 Dec. 31, 2018 Notional amount $ 6,194,936 $ 5,743,283 Weighted average pay rate on interest-rate swaps 3.67 % 3.64 % Weighted average receive rate on interest rate swaps 3.67 % 3.64 % Weighted average maturity (years) 11 11 Fair value of interest rate swap derivatives (asset) $ 130,122 $ 92,475 Fair value of interest rate swap derivatives (liability) $ 130,790 $ 92,892

Leases

Leases	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	NOTE 11: Leases In February 2016, the FASB established Topic 842, Leases, by issuing Accounting Standards Update (ASU) No. 2016-02, which requires lessees to recognize leases on-balance sheet and disclose key information about leasing arrangements. Subsequently, amendments ASU No. 2018-01, Land Easement Practical Expedient for Transition to Topic 842; ASU No. 2018-10, Codification Improvements to Topic 842, Leases; and ASU No. 2018-11, Targeted Improvements were issued. ASC 842 establishes a right-of-use (“ROU”) model that requires a lessee to recognize a ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. Leases are classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. The Company leases certain properties and equipment under operating leases that resulted in the recognition of ROU Lease Assets of $21,143 and Lease Liabilities of $22,657 on the Company’s Condensed Consolidated Balance Sheets. The one-time transition impact to retained earnings from measurement differences was approximately $1,464 as disclosed on the Company’s Condensed Consolidated Statements of Changes in Stockholders’ Equity. ASC 842 was effective on January 1, 2019. A modified retrospective transition approach is required, applying the new standard to all leases existing at the date of initial application. The Company chose to use the effective date approach. As such, all periods presented after January 1, 2019 are under ASC 842 whereas periods presented prior to January 1, 2019 are in accordance with prior lease accounting of ASC 840. Financial information was not updated and the disclosures required under ASC 842 was not provided for dates and periods before January 1, 2019. ASC 842 provides a number of optional practical expedients in transition. The Company has elected the ‘package of practical expedients,’ which permits the Company not to reassess under the new standard the prior conclusions about lease identification, lease classification and initial direct costs. The Company also elected the use of the hindsight, a practical expedient which permits the use of information available after lease inception to determine the lease term via the knowledge of renewal options exercised not available as of the leases inception. The practical expedient pertaining to land easements is not applicable to the Company. ASC 842 also requires certain accounting elections for ongoing application of ASC 842. The Company elected the short-term lease recognition exemption for all leases that qualify, meaning those with terms under twelve months. ROU assets or lease liabilities are not to be recognized for short-term leases. However, since all real estate and equipment leases have terms greater than 12 months, no leases currently meet this exemption. The Company also elected the practical expedient to not separate lease and non-lease components for all leases, the majority of which consist of real estate common area maintenance expenses. However, since these non-lease items are subject to change, they are treated and disclosed as variable payments in the quantitative disclosures below. Consequently, ASC 842’s changed guidance on contract components will not significantly affect our financial reporting. Similarly, ASC 842’s narrowed definition of initial direct costs will not significantly affect financial reporting. Lessee Leases The majority of the Company’s lessee leases are operating leases, and consist of leased real estate for branches and operations centers. Options to extend and renew leases are generally exercised under normal circumstances. Advance notification is required prior to termination, and any noticing period is often limited to the months prior to renewal. Variable payments generally consist of common area maintenance and taxes. Rent escalations are generally specified by a payment schedule, or are subject to a defined formula. The Company also elected the practical expedient to not separate lease and non-lease components for all leases, the majority of which consist of real estate common area maintenance expenses. Generally, leases do not include guaranteed residual values, but instead typically specify that the leased premises are to be returned in satisfactory condition with the Company liable for damages. The Company also has other operating leases for various equipment, including copiers, printers, and other small equipment. Equipment lease terms and conditions generally specify a fixed amount and term with options to renew. The Company’s equipment leases are typically not renewed, and existing leases are typically assumed from prior bank acquisitions. For operating leases, the lease liability and ROU asset (before adjustments) are recorded at the present value of future lease payments. ASC 842 requires the use of the lease interest rate; however, this rate is typically not known. As an alternative, ASC 842 permits the use of an entity’s fully secured incremental borrowing rate. The Company is electing to utilize the FHLB Atlanta Fixed Rate Advance index, as it is the most actively used institution-specific collateralized borrowing source available to the Company. The Company also holds a small number of finance leases assumed in connection to prior acquisitions. These leases are all real estate leases. Terms and conditions are similar to those real estate operating leases described above, but the lease terms are generally longer. Lease classifications from the acquired institution were retained, and were again retained as a result of the election of the package of practical expedients described above. Three-month period ended Mar. 31, 2019 Amortization of ROU Assets - Finance Leases $ 38 Interest on Lease Liabilities - Finance Leases 50 Operating Lease Cost (Cost resulting from lease payments) 1,287 Short-term Lease Cost — Variable Lease Cost (Cost excluded from lease payments) 235 Sublease Income — Total Lease Cost $ 1,610 Finance Lease - Operating Cash Flows 57 Finance Lease - Financing Cash Flows 91 Operating Lease - Operating Cash Flows (Fixed Payments) 1,241 Operating Lease - Operating Cash Flows (Liability Reduction) 1,181 New ROU Assets - Operating Leases 21,351 New ROU Assets - Finance Leases — Weighted Average Lease Term (Years) - Finance Leases 9.22 Weighted Average Lease Term (Years) - Operating Leases 7.65 Weighted Average Discount Rate - Finance Leases 5.95 % Weighted Average Discount Rate - Operating Leases 3.65 % A maturity analysis of operating lease liabilities and reconciliation of the undiscounted cash flows to the total operating lease liabilities as of March 31, 2019 is as follows: Mar. 31, 2019 Operating lease payments due: Within one year $ 5,310 After one but within two years 4,257 After two but within three years 3,665 After three but within four years 2,599 After four years but within five years 2,136 After five years 7,896 Total undiscounted cash flows 25,863 Discount on cash flows (3,206 ) Total operating lease liabilities $ 22,657 The following is a schedule of future minimum annual rentals under operating leases as of December 31, 2018: Year ending December 31, 2018 $ 6,524 2019 5,096 2020 4,411 2021 3,633 2022 2,558 Thereafter 11,088 $ 33,310 Lessor Leases ASC 842 also impacted lessor accounting. ASC 842 changed the criteria in which a lessor lease is classified. A lease is a sales-type lease if any one of five criteria are met, each of which indicate that the lease, in effect, transfers control of the underlying asset to the lessee. If none of those five criteria are met, but two additional criteria are both met, indicating that the lessor has transferred substantially all the risks and benefits of the underlying asset to the lessee and a third party, the lease is a direct financing lease. All leases that are not sales-type or direct financing leases are operating leases. Similar to the above lessee leases, the Company has elected the ‘package of practical expedients,’ which allows the Company not to reassess the Company’s prior conclusions under ASC 842 about lease identification, lease classification and initial direct costs. The Company also elected the use of the hindsight, a practical expedient which permits the use of information available after lease inception to determine the lease term via the knowledge of renewal options exercised not available as of the leases inception. Lastly, the practical expedient pertaining to land easements is not applicable to the Company. While ASC 842 identifies common area building maintenance as a non-lease component of our real estate lease contracts, the Company elected to account for the Company’s real estate leases and associated common area maintenance service components as a single, combined operating lease component. Consequently, ASC 842’s changed guidance on contract components will not significantly affect financial reporting. Substantially, all of the Company’s lessor leases are related to unused real estate office space owned by the Company. Most have defined terms, though some leases have gone month-to-month once the initial term has passed. The impact of subleases is not material. Income from operating leases are reported within Occupancy Expense as an offset to Non-interest Expense in the Company’s Condensed Consolidated Statements of Income and Comprehensive Income. The Company is also the lessor on a few equipment direct finance leases (formerly known as capital leases) with three municipal entities. Interest income from these leases are tax exempt, and is reported within loan interest income. The lessee retains the title to all equipment in each of these finance leases. Each of these leases originated in 2018, and therefore the prior ASC 840 classification was not reassessed due to the election of the package of practical expedients. Three-month period ended Mar. 31, 2019 Operating Lease Income from Lease Payments $ 212 Direct Financing Lease Income 173 Direct Financing Profit Recognized at Commencement Date — Lease Income Related to Variable lease Payments not included in measurement of lease receivable — Total Lease Income 385 Net Investment in Direct Financing Leases 15,785 Unguaranteed Residual Assets — Deferred Selling Profit on Direct Financing Leases — Maturity Analysis of Operating Lease Receivables 0 - 12 Months 962 13 - 24 Months 551 25 - 36 Months 341 37 - 48 Months 166 48 - 60 Months 6 Over 60 Months — Maturity Analysis of Finance Lease Receivables 0 - 12 Months 1,392 13 - 24 Months 1,841 25 - 36 Months 1,618 37 - 48 Months 1,356 48 - 60 Months 1,355 Over 60 Months 12,543

Recently Issued Accounting Stan

Recently Issued Accounting Standards	3 Months Ended
	Mar. 31, 2019
Accounting Changes And Error Corrections [Abstract]
Recently Issued Accounting Standards	NOTE 12: Recently Issued Accounting Standards 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 including evaluating the impact from the loans acquired from the recent acquisitions . 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 . T he 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 computing the implied fair value of goodwill under Step 2, an entity had to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities (including unrecognized assets and liabilities) following the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. Instead, under the amendments in this update, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. FASB also eliminated the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails that qualitative test, to perform Step 2 of the goodwill impairment test. Therefore, the same impairment assessment applies to all reporting units. An entity is required to disclose the amount of goodwill allocated to each reporting unit with a zero or negative carrying amount of net assets. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The amendments in this update become effective for annual periods and interim periods within those annual periods beginning after December 15, 2019. 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. 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 adopted the new accounting guidance effective January 1, 2019, but it did not have a material impact on the Consolidated Financial Statements. 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 adopted the new accounting guidance effective January 1, 2019, but it d id not have a material impact on the Co nsolidated Financial Statements . 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.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Note 13: Subsequent Events Completed Acquisition of National Commerce Corporation On April 1, 2019, the Company completed its previously announced acquisition of National Commerce Corporation (“NCOM”), whereby NCOM merged 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 NCOM’s subsidiary bank, National Bank of Commerce (“NBC”), merged with CenterState Bank as the surviving bank. Under the terms of the agreement, each outstanding share of NCOM common stock converted into the right to receive 1.65 shares of the Company’s common stock and cash in lieu of any fractional shares of CenterState common stock. The merger consideration, which was mainly comprised of Company common stock, was approximately $825,464. The Company’s primary reasons for the transaction were 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. During the three months ended March 31, 2019, the Company incurred approximately $1,264 of acquisition costs related to this transaction. These acquisition costs are reported in merger and acquisition related expenses on the Company’s Consolidated Statements of Income and Comprehensive Income. The majority of the acquisition costs for this transaction are expected to be recorded during the second and third quarters of 2019. Additional disclosures required by ASC 805 have been omitted because the information needed for the disclosures is not available due to the close proximity of the closing of this transaction with the date these financial statements are being issued. NCOM, which wa s headquartered in Birmingham, Alabama, operated 37 banking locations. As of March 31, 2019 , NCOM reported total assets of $ , total loans of $ and total deposits of $ .

Common Stock Outstanding and _2

Common Stock Outstanding and Earnings Per Share Data (Tables)	3 Months Ended
	Mar. 31, 2019
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. Three months ended March 31, 2019 2018 Basic Net income available to common shareholders $ 44,643 $ 35,636 Less: Earnings allocated to participating securities (23 ) (29 ) Net income allocated to common shareholders $ 44,620 $ 35,607 Weighted average common shares outstanding including participating securities 95,790,456 83,208,874 Less: Participating securities (1) (49,600 ) (69,133 ) Average shares 95,740,856 83,139,741 Basic earnings per common share $ 0.47 $ 0.43 Diluted Net income available to common shareholders $ 44,620 $ 35,607 Weighted average common shares outstanding for basic earnings per common share 95,740,856 83,139,741 Add: Dilutive effects of stock based compensation awards 759,884 1,461,183 Average shares and dilutive potential common shares 96,500,740 84,600,924 Diluted earnings per common share $ 0.46 $ 0.42 (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.

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2019
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 Quoted prices Significant in active other Significant markets for observable unobservable Carrying identical assets inputs inputs value (Level 1) (Level 2) (Level 3) at March 31, 2019 Assets: Available for sale debt securities Corporate debt securities $ 5,094 — $ 5,094 — Obligations of U.S. government sponsored entities and agencies 36,356 — 36,356 — Mortgage backed securities 1,569,253 — 1,569,253 — Municipal securities 90,693 — 90,693 — Loans held for sale, at fair value 49,474 — 49,474 — Mortgage servicing assets 1,532 — 1,532 — Mortgage banking derivatives 1,512 — 4 1,508 Interest rate swap derivatives 130,122 — 130,122 — Liabilities: Mortgage banking derivatives 341 — 335 6 Interest rate swap derivatives 130,790 — 130,790 — 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 —
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 March 31, 2019 Assets: Impaired loans Residential real estate $ 1,518 — — $ 1,518 Commercial real estate 7,294 — — 7,294 Land, land development and construction 91 — — 91 Commercial 2,364 — — 2,364 Consumer 31 — — 31 Other real estate owned Residential real estate 32 — — 32 Commercial real estate — — — — Land, land development and construction 813 — — 813 Bank property held for sale 4,635 — — 4,635 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 Residential real estate — — — — Commercial real estate — — — — Land, land development and construction 867 — — 867 Bank property held for sale 5,805 — — 5,805
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 March 31, 2019 Carrying amount Level 1 Level 2 Level 3 Total Financial assets: Cash and cash equivalents $ 595,803 $ 595,803 $ — $ — $ 595,803 Available for sale debt securities 1,701,396 — 1,701,396 — 1,701,396 Held to maturity debt securities 214,240 — 215,175 — 215,175 Loans held for sale, at fair value 49,474 — 49,474 — 49,474 Loans, net 8,309,343 — — 8,355,012 8,355,012 Mortgage servicing assets 1,532 — 1,532 — 1,532 Mortgage banking derivatives 1,512 — 4 1,508 1,512 Interest rate swap derivatives 130,122 — 130,122 — 130,122 Accrued interest receivable 35,336 — 8,069 27,267 35,336 Financial liabilities: Deposits- without stated maturities $ 7,825,895 $ 7,825,895 $ — $ — $ 7,825,895 Deposits- with stated maturities 1,921,130 — 1,924,046 — 1,924,046 Securities sold under agreement to repurchase 59,031 — 59,031 — 59,031 Federal funds purchased and other borrowings 514,017 — 514,017 — 514,017 Corporate debentures 32,503 — — 28,562 28,562 Mortgage banking derivatives 341 — 335 6 341 Interest rate swap derivatives 130,790 — 130,790 — 130,790 Accrued interest payable 3,224 — 3,224 — 3,224 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 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

Reportable Segments (Tables)

Reportable Segments (Tables)	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Reconciliation of Reportable Segment Revenues, Expenses and Profit	The table below is a reconciliation of the reportable segment revenues, expenses, and profit to the Company’s consolidated total for the three-month periods ending March 31, 2019 and 2018. Three-month period ending March 31, 2019 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 127,832 $ 4,450 $ — $ — $ 132,282 Interest expense (14,851 ) (2,549 ) (707 ) — (18,107 ) Net interest income (expense) 112,981 1,901 (707 ) — 114,175 Provision for loan losses (1,015 ) (38 ) — — (1,053 ) Non-interest income 20,300 9,000 — — 29,300 Non-interest expense (77,581 ) (5,713 ) (1,179 ) — (84,473 ) Net income (loss) before taxes 54,685 5,150 (1,886 ) — 57,949 Income tax (provision) benefit (12,690 ) (1,305 ) 689 — (13,306 ) Net income $ 41,995 $ 3,845 $ (1,197 ) $ — $ 44,643 Total assets $ 11,939,930 $ 647,046 $ 2,073,703 $ (2,073,042 ) $ 12,587,637 Three-month period ending March 31, 2018 Correspondent Corporate Commercial banking and overhead and retail capital markets and Elimination banking division administration entries Total Interest income $ 100,969 $ 2,190 $ — $ — $ 103,159 Interest expense (6,207 ) (1,072 ) (862 ) — (8,141 ) Net interest income (expense) 94,762 1,118 (862 ) — 95,018 Provision for loan losses (1,162 ) (138 ) — — (1,300 ) Non-interest income 14,915 8,123 — — 23,038 Non-interest expense (69,997 ) (5,610 ) (389 ) — (75,996 ) Net income (loss) before taxes 38,518 3,493 (1,251 ) — 40,760 Income tax (provision) benefit (8,499 ) (885 ) 4,260 — (5,124 ) Net income $ 30,019 $ 2,608 $ 3,009 $ — $ 35,636 Total assets $ 9,843,219 $ 499,678 $ 1,585,585 $ (1,580,486 ) $ 10,347,996

Investment securities (Tables)

Investment securities (Tables)	3 Months Ended
	Mar. 31, 2019
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 debt securities and the related gross unrealized gains and losses recognized in accumulated other comprehensive income (loss) were as follows: March 31, 2019 Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value Corporate debt securities $ 5,000 $ 94 $ — $ 5,094 Obligations of U.S. government sponsored entities and agencies 36,894 6 544 36,356 Mortgage-backed securities 1,572,732 8,939 12,418 1,569,253 Municipal securities 87,927 2,766 — 90,693 Total available for sale debt securities $ 1,702,553 $ 11,805 $ 12,962 $ 1,701,396 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
Schedule of Sales of Available for Sale Securities	Sales of available for sale debt securities for the three months ended March 31, 2019 and 2018 were as follows: For the three months ended: March 31, 2019 March 31, 2018 Proceeds $ 66,486 $ 355,652 Gross gains 646 68 Gross losses 629 90
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 March 31, 2019 and December 31, 2018. March 31, 2019 Gross Gross Amortized Unrecognized Unrecognized Fair Cost Gains Losses Value Mortgage-backed securities $ 82,517 $ — $ 1,269 $ 81,248 Municipal securities 131,723 2,393 189 133,927 Total held to maturity debt securities $ 214,240 $ 2,393 $ 1,458 $ 215,175 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
Available-for-sale Securities [Member]
Fair Value and Amortized Cost of Investment Securities by Contractual Maturity	The fair value of available for sale debt securities at March 31, 2019 by contractual maturity were as follows. Securities not due at a single maturity date, primarily mortgage-backed securities, are shown separately. Fair Amortized Available for sale debt securities: Value Cost Due one year or less $ 661 $ 661 Due after one year through five years 6,911 6,851 Due after five years through ten years 29,959 29,793 Due after ten years through thirty years 94,612 92,516 Mortgage-backed securities 1,569,253 1,572,732 Total available for sale debt securities $ 1,701,396 $ 1,702,553
Investments Gross Unrealized Losses and Fair Value	The following tables show the Company’s available for sale debt investments’ gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at March 31, 2019 and December 31, 2018. March 31, 2019 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses Obligations of U.S. government sponsored entities and agencies $ 18,135 $ 220 $ 16,323 $ 324 $ 34,458 $ 544 Mortgage backed securities 947 10 990,146 12,408 991,093 12,418 Total temporarily impaired available for sale debt securities $ 19,082 $ 230 $ 1,006,469 $ 12,732 $ 1,025,551 $ 12,962 December 31, 2018 Less than 12 months 12 months or more Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses 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
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 securities at March 31, 2019 by contractual maturity were as follows. Mortgage-backed securities are not due at a single maturity date and are shown separately. Fair Amortized Held to maturity debt securities Value Cost Due after five years through ten years $ 2,064 $ 2,041 Due after ten years through thirty years 131,863 129,682 Mortgage-backed securities 81,248 82,517 Total held to maturity debt securities $ 215,175 $ 214,240
Investments Gross Unrealized Losses and Fair Value	The following table shows 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 March 31, 2019 and December 31, 2018. March 31, 2019 Less than 12 months 12 months or more Total Fair Unrecognized Fair Unrecognized Fair Unrecognized Value Losses Value Losses Value Losses Mortgage backed securities $ — $ — $ 81,248 $ 1,269 $ 81,248 $ 1,269 Municipal securities — — 19,637 189 19,637 189 Total temporarily impaired held to maturity debt securities $ — $ — $ 100,885 $ 1,458 $ 100,885 $ 1,458 December 31, 2018 Less than 12 months 12 months or more Total Fair Unrecognized Fair Unrecognized Fair Unrecognized Value Losses Value Losses 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

Loans Held for Sale (Tables)

Loans Held for Sale (Tables)	3 Months Ended
	Mar. 31, 2019
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 during the three-month periods ending March 31, 2019 and 2018. Three-month periods ended Mar. 31, 2019 Mar. 31, 2018 Beginning balance $ 40,399 $ 19,647 Effect from acquisitions — 6,124 Loans originated 134,752 58,098 Proceeds from sales (129,657 ) (57,321 ) Net change in fair value 4 363 Net realized gain on sales 3,976 1,574 Ending balance $ 49,474 $ 28,485
Summary of Notional Amounts for Interest Rate Lock Commitments, 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 March 31, 2019 and 2018. Notional at March 31, 2019 March 31, 2018 Interest rate lock commitments $ 85,802 $ 45,488 Best efforts forward trades 92,115 62,426 MBS forward trades 57,000 — Total derivative instruments $ 234,917 $ 107,914

Loans (Tables)

Loans (Tables)	3 Months Ended
	Mar. 31, 2019
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 the dates indicated. March 31, 2019 December 31, 2018 Loans excluding PCI loans Real estate loans Residential $ 1,762,696 $ 1,702,114 Commercial 4,400,583 4,454,098 Land, development and construction 651,112 635,562 Total real estate 6,814,391 6,791,774 Commercial 1,175,966 1,183,380 Consumer and other loans 206,545 203,686 Loans before unearned fees and deferred cost 8,196,902 8,178,840 Net unearned fees and costs 3,037 2,693 Total loans excluding PCI loans 8,199,939 8,181,533 PCI loans (note 1) Real estate loans Residential 55,532 58,804 Commercial 80,792 87,336 Land, development and construction 7,261 7,028 Total real estate 143,585 153,168 Commercial 5,662 5,594 Consumer and other loans 209 209 Total PCI loans 149,456 158,971 Total loans 8,349,395 8,340,504 Allowance for loan losses for loans that are not PCI loans (39,861 ) (39,579 ) Allowance for loan losses for PCI loans (191 ) (191 ) Total loans, net of allowance for loan losses $ 8,309,343 $ 8,300,734 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 table below set forth the activity in the allowance for loan losses for the periods presented. Allowance for loan losses for loans that are not PCI loans Allowance for loan losses on PCI loans Total Three months ended March 31, 2019 Balance at beginning of period $ 39,579 $ 191 $ 39,770 Loans charged-off (1,447 ) — (1,447 ) Recoveries of loans previously charged-off 676 — 676 Net charge-offs (771 ) — (771 ) Provision for loan losses 1,053 — 1,053 Balance at end of period $ 39,861 $ 191 $ 40,052 Three months ended March 31, 2018 Balance at beginning of period $ 32,530 $ 295 $ 32,825 Loans charged-off (403 ) — (403 ) Recoveries of loans previously charged-off 632 75 707 Net recoveries 229 75 304 Provision for loan losses 1,395 (95 ) 1,300 Balance at end of period $ 34,154 $ 275 $ 34,429 The following tables present the activity in the allowance for loan losses by portfolio segment for the periods presented. Real Estate Loans Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses for loans that are not PCI loans: Three months ended March 31, 2019 Beginning of the period $ 5,518 $ 22,978 $ 1,781 $ 6,414 $ 2,888 $ 39,579 Charge-offs (201 ) — (31 ) (664 ) (551 ) (1,447 ) Recoveries 142 152 83 155 144 676 Provision for loan losses (11 ) (883 ) 387 1,025 535 1,053 Balance at end of period $ 5,448 $ 22,247 $ 2,220 $ 6,930 $ 3,016 $ 39,861 Three months ended March 31, 2018 Beginning of the period $ 6,003 $ 19,304 $ 1,179 $ 4,130 $ 1,914 $ 32,530 Charge-offs (136 ) — — (7 ) (260 ) (403 ) Recoveries 274 94 — 6 258 632 Provision for loan losses (394 ) 1,577 115 372 (275 ) 1,395 Balance at end of period $ 5,747 $ 20,975 $ 1,294 $ 4,501 $ 1,637 $ 34,154 Real Estate Loans Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses for loans that are PCI loans: Three months ended March 31, 2019 Beginning of the period $ — $ — $ 177 $ — $ 14 $ 191 Charge-offs — — — — — — Recoveries — — — — — — Provision for loan losses — — — — — — Balance at end of period $ — $ — $ 177 $ — $ 14 $ 191 Three months ended March 31, 2018 Beginning of the period $ — $ 59 $ 222 $ — $ 14 $ 295 Charge-offs — — — — — — Recoveries — — 75 — — 75 Provision for loan losses — — (95 ) — — (95 ) Balance at end of period $ — $ 59 $ 202 $ — $ 14 $ 275
Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment and Based on Impairment Method	The following tables present the balance in the allowance for loan losses and the recorded investment in loans by portfolio segment and based on impairment method as of March 31, 2019 and December 31, 2018. Accrued interest receivable and unearned loan fees and costs are not included in the recorded investment because they are not material. Real Estate Loans As of March 31, 2019 Residential Commercial Land, develop., constr. Comm. & industrial Consumer & other Total Allowance for loan losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 324 $ 761 $ — $ 1,389 $ 1 $ 2,475 Collectively evaluated for impairment 5,124 21,486 2,220 5,541 3,015 37,386 Purchased credit impaired — — 177 — 14 191 Total ending allowance balance $ 5,448 $ 22,247 $ 2,397 $ 6,930 $ 3,030 $ 40,052 Loans: Individually evaluated for impairment $ 5,657 $ 8,078 $ 116 $ 3,492 $ 134 $ 17,477 Collectively evaluated for impairment 1,757,039 4,392,505 650,996 1,172,474 206,411 8,179,425 Purchased credit impaired 55,532 80,792 7,261 5,662 209 149,456 Total ending loan balances $ 1,818,228 $ 4,481,375 $ 658,373 $ 1,181,628 $ 206,754 $ 8,346,358 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
Summary of Impaired Loans	The table below summarizes impaired loan data for the periods presented. Mar. 31, 2019 Dec. 31, 2018 Performing TDRs (these are not included in nonperforming loans ("NPLs")) $ 8,801 $ 8,475 Nonperforming TDRs (these are included in NPLs) 1,092 1,002 Total TDRs (these are included in impaired loans) 9,893 9,477 Impaired loans that are not TDRs 7,584 6,223 Total impaired loans $ 17,477 $ 15,700
Troubled Debt Restructured Loans by Loans Type	TDRs as of March 31, 2019 and December 31, 2018 quantified by loan type classified separately as accrual (performing loans) and non-accrual (non-performing loans) are presented in the tables below. As of March 31, 2019 Accruing Non-Accrual Total Real estate loans: Residential $ 5,507 $ 489 $ 5,996 Commercial 1,823 563 2,386 Land, development, construction 76 40 116 Total real estate loans 7,406 1,092 8,498 Commercial 1,261 — 1,261 Consumer and other 134 — 134 Total TDRs $ 8,801 $ 1,092 $ 9,893 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
Summary of Loans by Class Modified	The following table presents loans by class modified and for which there was a payment default within twelve months following the modification during the periods ending March 31, 2019 and 2018. Period ending Period ending March 31, 2019 March 31, 2018 Number Recorded Number Recorded of loans investment of loans investment Residential — $ — — $ — Commercial real estate — — 1 174 Land, development, construction — — — — Commercial and Industrial 1 122 — — Consumer and other — — — — Total 1 $ 122 1 $ 174
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 March 31, 2019 and December 31, 2018, excluding purchased credit impaired loans accounted for pursuant to ASC Topic 310-30. The recorded investment is less than the unpaid principal balance due to partial charge-offs. As of March 31, 2019 Unpaid principal balance Recorded investment Allowance for loan losses allocated With no related allowance recorded: Residential real estate $ 3,030 $ 2,973 $ — Commercial real estate 5,469 4,799 — Land, development, construction 143 116 — Commercial and industrial 1,056 1,045 — Consumer, other 108 107 — With an allowance recorded: Residential real estate 2,859 2,684 324 Commercial real estate 3,423 3,279 761 Land, development, construction — — — Commercial and industrial 2,481 2,447 1,389 Consumer, other 32 27 1 Total $ 18,601 $ 17,477 $ 2,475 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
Summary of Impairment by Class of Loans	Three months ended March 31, 2019 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 5,945 $ 62 $ — Commercial 7,787 25 — Land, development, construction 117 1 — Total real estate loans 13,849 88 — Commercial and industrial 2,600 12 — Consumer and other loans 140 2 — Total $ 16,589 $ 102 $ — Three months ended March 31, 2018 Average of impaired loans Interest income recognized during impairment Cash basis interest income recognized Real estate loans: Residential $ 8,133 $ 77 $ — Commercial 8,264 12 — Land, development, construction 264 3 — Total real estate loans 16,661 92 — Commercial and industrial 3,025 6 — Consumer and other loans 195 2 — Total $ 19,881 $ 100 $ —
Summary of Nonperforming Loans	Nonperforming loans include both smaller balance homogeneous loans that are collectively evaluated for impairment and individually classified impaired loans, excluding purchased credit impaired loans accounted for pursuant to ASC Topic 310-30. Nonperforming loans were as follows: Mar. 31, 2019 Dec. 31, 2018 Non-accrual loans $ 35,181 $ 23,567 Loans past due over 90 days and still accruing interest — — Total non-performing loans $ 35,181 $ 23,567
Summary of Recorded Investment in Nonaccrual Loans and Loans Past Due Over 90 Days Still on Accrual by Class of Loans	The following table presents the recorded investment in nonaccrual loans and loans past due over 90 days still on accrual by class of loans as of March 31, 2019 and December 31, 2018, excluding purchased credit impaired loans: As of March 31, 2019 Nonaccrual Loans past due over 90 days still accruing Residential real estate $ 12,888 $ — Commercial real estate 10,259 — Land, development, construction 6,965 — Commercial 4,425 — Consumer, other 644 — Total $ 35,181 $ — As of December 31, 2018 Nonaccrual 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 $ —
Summary Aging of Recorded Investment in Past Due Loans	The following table presents the aging of the recorded investment in past due loans as of March 31, 2019 and December 31, 2018, excluding purchased credit impaired loans: 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 Nonaccrual Loans As of March 31, 2019 Residential real estate $ 1,762,696 $ 10,610 $ 3,172 $ — $ 13,782 $ 1,736,026 $ 12,888 Commercial real estate 4,400,583 7,012 4,856 — 11,868 4,378,456 10,259 Land/dev/construction 651,112 4,036 79 — 4,115 640,032 6,965 Commercial 1,175,966 3,532 368 — 3,900 1,167,641 4,425 Consumer 206,545 709 261 — 970 204,931 644 $ 8,196,902 $ 25,899 $ 8,736 $ — $ 34,635 $ 8,127,086 $ 35,181 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 Nonaccrual 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
Risk Category of Loans by Class of Loans, Excluding Purchased Credit Impaired Loans	As of March 31, 2019 Loan Category Pass Special Mention Substandard Doubtful Residential real estate $ 1,696,127 $ 38,771 $ 27,798 $ — Commercial real estate 4,210,370 144,831 45,382 — Land/dev/construction 632,862 14,109 4,141 — Commercial 1,127,102 41,986 6,878 — Consumer 205,470 224 851 — Total $ 7,871,931 $ 239,921 $ 85,050 $ — 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 $ —
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, based on payment activity as of March 31, 2019 and December 31, 2018: As of March 31, 2019 Residential Consumer Performing $ 1,749,808 $ 205,901 Nonperforming 12,888 644 Total $ 1,762,696 $ 206,545 As of December 31, 2018 Residential Consumer Performing $ 1,690,626 $ 203,121 Nonperforming 11,488 565 Total $ 1,702,114 $ 203,686
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 March 31, 2019 and December 31, 2018. Contractually required principal and interest payments have been adjusted for estimated prepayments. Mar. 31, 2019 Dec. 31, 2018 Contractually required principal and interest $ 248,243 $ 267,815 Non-accretable difference (28,865 ) (38,602 ) Cash flows expected to be collected 219,378 229,213 Accretable yield (69,922 ) (70,242 ) Carrying value of acquired loans 149,456 158,971 Allowance for loan losses (191 ) (191 ) Carrying value less allowance for loan losses $ 149,265 $ 158,780
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 three - month periods ending March 31, 2019 and 2018 . Activity during the Effect of income all other three-month period ending March 31, 2019 Dec. 31, 2018 acquisitions accretion adjustments Mar. 31, 2019 Contractually required principal and interest $ 267,815 $ — $ — $ (19,572 ) $ 248,243 Non-accretable difference (38,602 ) — — 9,737 (28,865 ) Cash flows expected to be collected 229,213 — — (9,835 ) 219,378 Accretable yield (70,242 ) — 10,140 (9,820 ) (69,922 ) Carry value of acquired loans $ 158,971 $ — $ 10,140 $ (19,655 ) $ 149,456 Activity during the Effect of income all other three-month period ending March 31, 2018 Dec. 31, 2017 acquisitions accretion adjustments Mar. 31, 2018 Contractually required principal and interest $ 248,283 $ 88,705 $ — $ (21,711 ) $ 315,277 Non-accretable difference (13,183 ) (38,164 ) — 1,110 (50,237 ) Cash flows expected to be collected 235,100 50,541 — (20,601 ) 265,040 Accretable yield (70,942 ) (6,278 ) 7,718 (2,355 ) (71,857 ) Carry value of acquired loans $ 164,158 $ 44,263 $ 7,718 $ (22,956 ) $ 193,183

Securities Sold Under Agreeme_2

Securities Sold Under Agreement to Repurchase (Tables)	3 Months Ended
	Mar. 31, 2019
Banking And Thrift [Abstract]
Summary of Repurchase Agreement	The following table provides additional details for the periods presented. MBS Municipal As of March 31, 2019 Securities Securities Total Market value of securities pledged $ 62,611 $ 442 $ 63,053 Borrowings related to pledged amounts 58,829 202 59,031 Market value pledged as a % of borrowings 106 % 219 % 107 % As of December 31, 2018 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 %

Business Combinations (Tables)

Business Combinations (Tables)	3 Months Ended
	Mar. 31, 2019
Pro-Forma Financial Information of Acquisition	Pro-forma data for the three-month period ending March 31, 2018 listed in the table below presents pro-forma information as if the Charter acquisitions occurred at the beginning of 2018. Three months ended March 31, 2018 Net interest income $ 112,182 Net income available to common shareholders $ 51,250 EPS - basic $ 0.54 EPS - diluted $ 0.53
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, 2018 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, 2018 $ 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 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 11,670 Other assets 6,135 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
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
HCBF Holding Company, Inc. [Member]
Summary of Purchase Price Calculation	The table below summarizes the purchase price calculation. Number of shares of Harbor common stock outstanding at December 31, 2018 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, 2018 $ 25.73 Fair value of CenterState common stock issued $ 387,279 Number of shares of Harbor common stock outstanding at December 31, 2018 22,299,082 Cash consideration each Harbor 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 Harbor common shareholders $ 430,211 Fair value of Harbor stock options converted to CenterState stock options $ 18,025 Total Purchase Price for Harbor $ 448,236
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 14,071 Other assets 2,536 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
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
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 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
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

Interest Rate Swap Derivatives

Interest Rate Swap Derivatives (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Summary Information about the Interest Rate Swap Derivative Instruments	Summary information about the interest rate swap derivative instruments is as follows: Mar. 31, 2019 Dec. 31, 2018 Notional amount $ 6,194,936 $ 5,743,283 Weighted average pay rate on interest-rate swaps 3.67 % 3.64 % Weighted average receive rate on interest rate swaps 3.67 % 3.64 % Weighted average maturity (years) 11 11 Fair value of interest rate swap derivatives (asset) $ 130,122 $ 92,475 Fair value of interest rate swap derivatives (liability) $ 130,790 $ 92,892

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Schedule of Lessee Leases	Three-month period ended Mar. 31, 2019 Amortization of ROU Assets - Finance Leases $ 38 Interest on Lease Liabilities - Finance Leases 50 Operating Lease Cost (Cost resulting from lease payments) 1,287 Short-term Lease Cost — Variable Lease Cost (Cost excluded from lease payments) 235 Sublease Income — Total Lease Cost $ 1,610 Finance Lease - Operating Cash Flows 57 Finance Lease - Financing Cash Flows 91 Operating Lease - Operating Cash Flows (Fixed Payments) 1,241 Operating Lease - Operating Cash Flows (Liability Reduction) 1,181 New ROU Assets - Operating Leases 21,351 New ROU Assets - Finance Leases — Weighted Average Lease Term (Years) - Finance Leases 9.22 Weighted Average Lease Term (Years) - Operating Leases 7.65 Weighted Average Discount Rate - Finance Leases 5.95 % Weighted Average Discount Rate - Operating Leases 3.65 %
Schedule of Maturity Analysis of Undiscounted Cash Flows of Operating Lease Liabilities	A maturity analysis of operating lease liabilities and reconciliation of the undiscounted cash flows to the total operating lease liabilities as of March 31, 2019 is as follows: Mar. 31, 2019 Operating lease payments due: Within one year $ 5,310 After one but within two years 4,257 After two but within three years 3,665 After three but within four years 2,599 After four years but within five years 2,136 After five years 7,896 Total undiscounted cash flows 25,863 Discount on cash flows (3,206 ) Total operating lease liabilities $ 22,657
Schedule of Future Minimum Annual Rentals under All Leases	The following is a schedule of future minimum annual rentals under operating leases as of December 31, 2018: Year ending December 31, 2018 $ 6,524 2019 5,096 2020 4,411 2021 3,633 2022 2,558 Thereafter 11,088 $ 33,310
Schedule of Lessor Leases	Three-month period ended Mar. 31, 2019 Operating Lease Income from Lease Payments $ 212 Direct Financing Lease Income 173 Direct Financing Profit Recognized at Commencement Date — Lease Income Related to Variable lease Payments not included in measurement of lease receivable — Total Lease Income 385 Net Investment in Direct Financing Leases 15,785 Unguaranteed Residual Assets — Deferred Selling Profit on Direct Financing Leases — Maturity Analysis of Operating Lease Receivables 0 - 12 Months 962 13 - 24 Months 551 25 - 36 Months 341 37 - 48 Months 166 48 - 60 Months 6 Over 60 Months — Maturity Analysis of Finance Lease Receivables 0 - 12 Months 1,392 13 - 24 Months 1,841 25 - 36 Months 1,618 37 - 48 Months 1,356 48 - 60 Months 1,355 Over 60 Months 12,543

Common Stock Outstanding and _3

Common Stock Outstanding and Earnings Per Share Data - Additional Information (Detail) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Anti dilutive stock options	0	0

Common Stock Outstanding and _4

Common Stock Outstanding and Earnings Per Share Data - Factors Used in Earnings Per Share Computations (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Basic
Net income available to common shareholders		$ 44,643	$ 35,636
Less: Earnings allocated to participating securities		(23)	(29)
Net income allocated to common shareholders		$ 44,620	$ 35,607
Weighted average common shares outstanding including participating securities		95,790,456	83,208,874
Less: Participating securities	[1]	(49,600)	(69,133)
Average shares	[2]	95,740,856	83,139,741
Basic earnings per common share		$ 0.47	$ 0.43
Diluted
Net income available to common shareholders		$ 44,620	$ 35,607
Weighted average common shares outstanding for basic earnings per common share	[2]	95,740,856	83,139,741
Add: Dilutive effects of stock based compensation awards		759,884	1,461,183
Average shares and dilutive potential common shares	[2]	96,500,740	84,600,924
Diluted earnings per common share		$ 0.46	$ 0.42
[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 shares.

Fair Value - Additional Informa

Fair Value - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans with allocated allowance for loan losses	$ 11,298		$ 8,829
Impaired valuation allowance	2,355		$ 1,463
Provision for loan loss expense on impaired loans	1,053	$ 1,300
Repossessed real estate owned valuation write down	108	187
Impairment on bank property held for sale	107	1,449
Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Provision for loan loss expense on impaired loans	$ 1,124	$ 68
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization rates to determine fair value of collateral	4.00%
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Capitalization rates to determine fair value of collateral	12.00%

Fair Value - Assets and Liabili

Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets:
Trading securities, at fair value		$ 1,737
Available for sale debt securities	$ 1,701,396	1,727,348
Loans held for sale, carrying value	49,474	40,399
Mortgage servicing assets, carrying amount	1,532	1,565
Mortgage banking derivatives, carrying amount assets	1,512	783
Interest rate swap derivatives, carrying amount assets	130,122	92,475
Liabilities:
Mortgage banking derivatives, carrying amount liability	341	169
Interest rate swap derivatives, carrying amount liability	130,790	92,892
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Trading securities, at fair value		1,737
Available for sale debt securities	1,701,396	1,727,348
Fair Value Measurements on Recurring [Member] | Carrying value [Member]
Assets:
Trading securities, at fair value		1,737
Loans held for sale, carrying value	49,474	40,399
Mortgage servicing assets, carrying amount	1,532	1,565
Mortgage banking derivatives, carrying amount assets	1,512	783
Interest rate swap derivatives, carrying amount assets	130,122	92,475
Liabilities:
Mortgage banking derivatives, carrying amount liability	341	169
Interest rate swap derivatives, carrying amount liability	130,790	92,892
Fair Value Measurements on Recurring [Member] | Carrying value [Member] | Corporate Debt Securities [Member]
Assets:
Available for sale debt securities	5,094	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	36,356	37,868
Fair Value Measurements on Recurring [Member] | Carrying value [Member] | Mortgage Backed Securities [Member]
Assets:
Available for sale debt securities	1,569,253	1,594,275
Fair Value Measurements on Recurring [Member] | Carrying value [Member] | Municipal Securities [Member]
Assets:
Available for sale debt securities	90,693	88,778
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Trading securities, at fair value		1,737
Loans held for sale, carrying value	49,474	40,399
Mortgage servicing assets, carrying amount	1,532	1,565
Mortgage banking derivatives, carrying amount assets	4
Interest rate swap derivatives, carrying amount assets	130,122	92,475
Liabilities:
Mortgage banking derivatives, carrying amount liability	335	164
Interest rate swap derivatives, carrying amount liability	130,790	92,892
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member]
Assets:
Available for sale debt securities	5,094	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	36,356	37,868
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage Backed Securities [Member]
Assets:
Available for sale debt securities	1,569,253	1,594,275
Fair Value Measurements on Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Municipal Securities [Member]
Assets:
Available for sale debt securities	90,693	88,778
Fair Value Measurements on Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Mortgage banking derivatives, carrying amount assets	1,508	783
Liabilities:
Mortgage banking derivatives, carrying amount liability	$ 6	$ 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	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans on Residential real estate at Carrying value	$ 1,518	$ 1,811
Impaired loans on Commercial real estate at Carrying value	7,294	5,614
Impaired loans on Land, land development and construction at Carrying value	91	90
Impaired loans on Commercial at Carrying value	2,364	1,274
Impaired loans on Consumer at Carrying value	31	40
Other real estate owned on Residential real estate at Carrying value	32
Other real estate owned on Land, land development and construction at Carrying value	813	867
Bank owned real estate held for sale	4,635	5,805
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	4,635	5,805
Impaired loans on Residential real estate	1,518	1,811
Impaired loans on Commercial real estate	7,294	5,614
Impaired loans on Land, land development and construction	91	90
Impaired loans on Commercial	2,364	1,274
Impaired loans on Consumer	31	40
Other real estate owned on Residential real estate	32
Other real estate owned on Land, land development and construction	$ 813	$ 867

Fair Value - Carrying Amounts a

Fair Value - Carrying Amounts and Estimated Fair Values of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Financial assets:
Cash and cash equivalents	$ 595,803	$ 367,333
Cash and cash equivalents, fair value	595,803	367,333
Trading securities, at fair value		1,737
Available for sale debt securities, at fair value	1,701,396	1,727,348
Held to maturity debt securities, carrying amount	214,240	216,833
Held to maturity debt securities, at fair value	215,175	212,179
Loans held for sale, carrying value	49,474	40,399
Loans held for sale, fair value	49,474	40,399	$ 28,485	$ 19,647
Loans, net, carrying amount	8,309,343	8,300,734
Loans, net, fair value	8,355,012	8,342,220
Mortgage servicing assets, carrying amount	1,532	1,565
Mortgage servicing assets, at fair value	1,532	1,565
Mortgage banking derivatives, carrying amount assets	1,512	783
Mortgage banking derivatives, assets fair value	1,512	783
Interest rate swap derivatives, carrying amount assets	130,122	92,475
Interest rate swap derivatives, assets fair value	130,122	92,475
Accrued interest receivable, carrying amount	35,336	33,143
Accrued interest receivable, fair value	35,336	33,143
Financial liabilities:
Deposits- without stated maturities, carrying amount	7,825,895	7,655,376
Deposits- without stated maturities, fair value	7,825,895	7,655,376
Deposits- with stated maturities, carrying amount	1,921,130	1,821,960
Deposits- with stated maturities, fair value	1,924,046	1,827,299
Securities sold under agreement to repurchase, fair value	59,031	57,772
Securities sold under agreement to repurchase	59,031	57,772
Federal funds purchased and other borrowings, carrying amount	514,017	655,360
Federal funds purchased and other borrowings, fair value	514,017	655,360
Corporate debentures, carrying amount	32,503	32,415
Corporate debentures, fair value	28,562	28,621
Mortgage banking derivatives, carrying amount liability	341	169
Mortgage banking derivatives, liability fair value	341	169
Interest rate swap derivatives, carrying amount	130,790	92,892
Interest rate swap derivatives, fair value	130,790	92,892
Accrued interest payable, carrying amount	3,224	2,627
Accrued interest payable, fair value	3,224	2,627
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets:
Cash and cash equivalents, fair value	595,803	367,333
Financial liabilities:
Deposits- without stated maturities, fair value	7,825,895	7,655,376
Significant Other Observable Inputs (Level 2) [Member]
Financial assets:
Trading securities, at fair value		1,737
Available for sale debt securities, at fair value	1,701,396	1,727,348
Held to maturity debt securities, at fair value	215,175	212,179
Loans held for sale, fair value	49,474	40,399
Mortgage servicing assets, at fair value	1,532	1,565
Mortgage banking derivatives, assets fair value	4
Interest rate swap derivatives, assets fair value	130,122	92,475
Accrued interest receivable, fair value	8,069	8,355
Financial liabilities:
Deposits- with stated maturities, fair value	1,924,046	1,827,299
Securities sold under agreement to repurchase, fair value	59,031	57,772
Federal funds purchased and other borrowings, fair value	514,017	655,360
Mortgage banking derivatives, liability fair value	335	164
Interest rate swap derivatives, fair value	130,790	92,892
Accrued interest payable, fair value	3,224	2,627
Significant Unobservable Inputs (Level 3) [Member]
Financial assets:
Loans, net, fair value	8,355,012	8,342,220
Mortgage banking derivatives, assets fair value	1,508	783
Accrued interest receivable, fair value	27,267	24,788
Financial liabilities:
Corporate debentures, fair value	28,562	28,621
Mortgage banking derivatives, liability fair value	$ 6	$ 5

Reportable Segments - Reconcili

Reportable Segments - Reconciliation of Reportable Segment Revenues, Expenses and Profit (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Interest income	$ 132,282	$ 103,159
Interest expense	(18,107)	(8,141)
Net interest income	114,175	95,018
Provision for loan losses	(1,053)	(1,300)
Non-interest income	29,300	23,038
Non-interest expense	(84,473)	(75,996)
Income before provision for income taxes	57,949	40,760
Income tax (provision) benefit	(13,306)	(5,124)
Net income	44,643	35,636
Total assets	12,587,637	10,347,996	$ 12,337,588
Operating Segments [Member] | Commercial and Retail Banking [Member]
Segment Reporting Information [Line Items]
Interest income	127,832	100,969
Interest expense	(14,851)	(6,207)
Net interest income	112,981	94,762
Provision for loan losses	(1,015)	(1,162)
Non-interest income	20,300	14,915
Non-interest expense	(77,581)	(69,997)
Income before provision for income taxes	54,685	38,518
Income tax (provision) benefit	(12,690)	(8,499)
Net income	41,995	30,019
Total assets	11,939,930	9,843,219
Operating Segments [Member] | Correspondent Banking And Capital Markets Division [Member]
Segment Reporting Information [Line Items]
Interest income	4,450	2,190
Interest expense	(2,549)	(1,072)
Net interest income	1,901	1,118
Provision for loan losses	(38)	(138)
Non-interest income	9,000	8,123
Non-interest expense	(5,713)	(5,610)
Income before provision for income taxes	5,150	3,493
Income tax (provision) benefit	(1,305)	(885)
Net income	3,845	2,608
Total assets	647,046	499,678
Corporate Overhead and Administration [Member]
Segment Reporting Information [Line Items]
Interest expense	(707)	(862)
Net interest income	(707)	(862)
Non-interest expense	(1,179)	(389)
Income before provision for income taxes	(1,886)	(1,251)
Income tax (provision) benefit	689	4,260
Net income	(1,197)	3,009
Total assets	2,073,703	1,585,585
Elimination Entries [Member]
Segment Reporting Information [Line Items]
Total assets	$ (2,073,042)	$ (1,580,486)

Investment Securities Available

Investment 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	Mar. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,702,553	$ 1,757,380
Gross Unrealized Gains	11,805	4,659
Gross Unrealized Losses	12,962	34,691
Fair Value	1,701,396	1,727,348
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,572,732	1,623,906
Gross Unrealized Gains	8,939	3,792
Gross Unrealized Losses	12,418	33,423
Fair Value	1,569,253	1,594,275
Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	87,927	88,415
Gross Unrealized Gains	2,766	698
Gross Unrealized Losses	0	335
Fair Value	90,693	88,778
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,000	6,265
Gross Unrealized Gains	94	162
Gross Unrealized Losses	0	0
Fair Value	5,094	6,427
Obligations of U.S. Government Sponsored Entities and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	36,894	38,794
Gross Unrealized Gains	6	7
Gross Unrealized Losses	544	933
Fair Value	$ 36,356	$ 37,868

Investment Securities Availab_2

Investment Securities Available for Sale - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2019USD ($)Security	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)Security
Schedule of Available-for-sale Securities [Line Items]
Tax provisions related to net realized gains	$ 4,000	$ (6,000)
Securities estimated fair value	$ 879,638,000		$ 961,721,000
Debt securities, Held-to-maturity, Restricted [Extensible List]	us-gaap:CollateralPledgedMember		us-gaap:CollateralPledgedMember
Percentage of AFS securities held by any one issuer as a percentage of stockholders' equity	10.00%		10.00%
Number of securities representing specified criteria | Security	0		0
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 Securities Availab_3

Investment Securities Available for Sale - Schedule of Sales of Available for Sale Securities (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Investments Debt And Equity Securities [Abstract]
Proceeds	$ 66,486	$ 355,652
Gross gains	646	68
Gross losses	$ 629	$ 90

Investment Securities Availab_4

Investment Securities Available for Sale - Fair Value and Amortized Cost of Investment Securities by Contractual Maturity (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Investments Debt And Equity Securities [Abstract]
Investment securities available for sale, Due in one year or less, Fair Value	$ 661
Investment securities available for sale, Due after one year through five years, Fair Value	6,911
Investment securities available for sale, Due after five years through ten years, Fair Value	29,959
Investment securities available for sale, Due after ten years through thirty years, Fair Value	94,612
Investment securities available for sale, Mortgage backed securities, Fair Value	1,569,253
Fair value	1,701,396
Investment securities available for sale, Due one year or less, Amortized Cost	661
Investment securities available for sale, Due after one year through five years, Amortized Cost	6,851
Investment securities available for sale, Due after five years through ten years, Amortized Cost	29,793
Investment securities available for sale, Due after ten years through thirty years, Amortized Cost	92,516
Investment securities available for sale, Mortgage backed securities, Amortized Cost	1,572,732
Amortized Cost	$ 1,702,553

Investment Securities Availab_5

Investment Securities Available for Sale - Investments Gross Unrealized Losses and Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 19,082	$ 698,058
Less than 12 months, Unrealized Losses	230	11,430
12 months or more, Fair Value	1,006,469	647,951
12 months or more, Unrealized Losses	12,732	23,261
Total, Fair Value	1,025,551	1,346,009
Total, Unrealized Losses	12,962	34,691
Obligations of U.S. Government Sponsored Entities and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	18,135	25,104
Less than 12 months, Unrealized Losses	220	332
12 months or more, Fair Value	16,323	9,398
12 months or more, Unrealized Losses	324	601
Total, Fair Value	34,458	34,502
Total, Unrealized Losses	544	933
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	947	647,923
Less than 12 months, Unrealized Losses	10	10,782
12 months or more, Fair Value	990,146	635,172
12 months or more, Unrealized Losses	12,408	22,641
Total, Fair Value	991,093	1,283,095
Total, Unrealized Losses	$ 12,418	33,423
Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value		25,031
Less than 12 months, Unrealized Losses		316
12 months or more, Fair Value		3,381
12 months or more, Unrealized Losses		19
Total, Fair Value		28,412
Total, Unrealized Losses		$ 335

Investment Securities Held to M

Investment Securities Held to Maturity - Fair Value of Held to Maturity Securities and Related Gross Unrecognized Gains and Losses (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 214,240	$ 216,833
Gross Unrecognized Gains	2,393	799
Gross Unrecognized Losses	1,458	5,453
Held-to-maturity securities, fair value	215,175	212,179
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	82,517	84,983
Gross Unrecognized Gains	0	0
Gross Unrecognized Losses	1,269	2,462
Held-to-maturity securities, fair value	81,248	82,521
Municipal Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	131,723	131,850
Gross Unrecognized Gains	2,393	799
Gross Unrecognized Losses	189	2,991
Held-to-maturity securities, fair value	$ 133,927	$ 129,658

Investment Securities Held to_2

Investment Securities Held to Maturity - Additional Information (Detail) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2019USD ($)Security	Sep. 30, 2018Security	Dec. 31, 2018USD ($)Security
Schedule of Held-to-maturity Securities [Line Items]
Number of securities representing specified criteria	0		0
Percentage of HTM securities held by any one issuer as a percentage of stockholders' equity	10.00%
Held to maturity securities pledged, carrying amount | $	$ 103,504		$ 103,710
Debt securities, available-for-sale, restriction type [extensible list]	us-gaap:CollateralPledgedMember		us-gaap:CollateralPledgedMember
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
Percentage of mortgage-backed securities held from U.S. government-sponsored entities and agencies	100.00%

Investment Securities Held to_3

Investment Securities Held to Maturity - Fair Value and Amortized Cost of Investment Securities by Contractual Maturity (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Investments Debt And Equity Securities [Abstract]
Investment securities held-to-maturity, Due after five years through ten years, Fair Value	$ 2,064
Investment securities held-to-maturity, Due after ten years through thirty years, Fair Value	131,863
Investment securities held-to-maturity, Mortgage backed securities, Fair Value	81,248
Held-to- maturity, Fair Value	215,175
Investment securities held-to-maturity, Due after five years through ten years, Amortized Cost	2,041
Investment securities held-to-maturity, Due after ten years through thirty years, Amortized Cost	129,682
Investment securities held-to-maturity, Mortgage backed securities, Amortized Cost	82,517
Held-to-maturity, Amortized Cost	$ 214,240

Investment Securities Held to_4

Investment Securities Held to Maturity - Investments Gross Unrecognized Losses and Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, Fair Value		$ 22,560
Less than 12 months, Unrecognized Losses		203
12 months or more, Fair Value	$ 100,885	130,328
12 months or more, Unrecognized Losses	1,458	5,250
Total, Fair Value	100,885	152,888
Total, Unrecognized Losses	1,458	5,453
Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
12 months or more, Fair Value	81,248	82,521
12 months or more, Unrecognized Losses	1,269	2,462
Total, Fair Value	81,248	82,521
Total, Unrecognized Losses	1,269	2,462
Municipal Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months, Fair Value		22,560
Less than 12 months, Unrecognized Losses		203
12 months or more, Fair Value	19,637	47,807
12 months or more, Unrecognized Losses	189	2,788
Total, Fair Value	19,637	70,367
Total, Unrecognized Losses	$ 189	$ 2,991

Loans Held for Sale - Additiona

Loans Held for Sale - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Loans Receivable Held For Sale Net [Line Items]
Net gains from changes in estimated fair value of mortgage loans held for sale	$ 4,000	$ 363,000
Total unpaid principal balance of loans held for sale	49,470,000		$ 39,318,000
Loans held for sale, past due	0
Loans held for sale, on nonaccrual	0
Net realized gain on sales of loans held for sale	3,976,000	1,574,000
Mortgage servicing fee	93,000
Mortgage servicing asset loss	33,000
Change in fair value of residential loans held for sale	4,000	363,000
Mortgage Banking Derivatives [Member]
Loans Receivable Held For Sale Net [Line Items]
Net unrealized gain on mortgage banking derivatives	557,000	$ 665,000
Mortgage hedge loss	$ 404,000

Loans Held for Sale - Summary o

Loans Held for Sale - Summary of Activity in Mortgage Loans Held for Sale (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Loans Receivable Held For Sale Net [Abstract]
Beginning balance	$ 40,399	$ 19,647
Effect from acquisitions		6,124
Loans originated	134,752	58,098
Proceeds from sales	(129,657)	(57,321)
Net gains from changes in estimated fair value of mortgage loans held for sale	4	363
Net realized gain on sales	3,976	1,574
Ending balance	$ 49,474	$ 28,485

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 Pertaining To Loans Held For Sale (Detail) - Loans Held for Sale [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Loans Held For Sale [Line Items]
Total derivative instruments	$ 234,917	$ 107,914
Interest Rate Lock Commitments [Member]
Loans Held For Sale [Line Items]
Total derivative instruments	85,802	45,488
Best Efforts Forward Trades [Member]
Loans Held For Sale [Line Items]
Total derivative instruments	92,115	$ 62,426
MBS Forward Trades [Member]
Loans Held For Sale [Line Items]
Total derivative instruments	$ 57,000

Loans - Summary of Information

Loans - Summary of Information Concerning Loan Portfolio by Collateral Types (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Receivables with Imputed Interest [Line Items]
Total loans excluding purchased credit impaired loans	$ 8,199,939	$ 8,181,533
Total PCI loans	149,456	158,971
Total loans	8,349,395	8,340,504
Allowance for loan losses for loans that are not PCI loans	(39,861)	(39,579)
Net Loans	8,309,343	8,300,734
Allowance for loan losses for loans that are not PCI loans [Member]
Receivables with Imputed Interest [Line Items]
Real estate loans, Residential	1,762,696	1,702,114
Real estate loans, Commercial	4,400,583	4,454,098
Land, development and construction	651,112	635,562
Total real estate	6,814,391	6,791,774
Commercial	1,175,966	1,183,380
Consumer and other loans	206,545	203,686
Loans before unearned fees and deferred cost	8,196,902	8,178,840
Net unearned fees and costs	3,037	2,693
Allowance for loan losses on PCI loans [Member]
Receivables with Imputed Interest [Line Items]
Real estate loans, Residential	55,532	58,804
Real estate loans, Commercial	80,792	87,336
Land, development and construction	7,261	7,028
Total real estate	143,585	153,168
Commercial	5,662	5,594
Consumer and other loans	209	209
Allowance for loan losses for PCI loans	$ (191)	$ (191)

Loans - Summary of Allowance fo

Loans - Summary of Allowance for Loan Losses and Recorded Investment in Loans by Portfolios (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 39,770	$ 32,825
Loans charged-off	(1,447)	(403)
Recoveries of loans previously charged-off	676	707
Net (charge-offs) recoveries	(771)	304
Provision for loan losses	1,053	1,300
Balance at end of period	40,052	34,429
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	5,518
Balance at end of period	5,448
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	22,978
Balance at end of period	22,247
Land, Development, Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	1,958
Balance at end of period	2,397
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	6,414
Balance at end of period	6,930
Consumer and Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	2,902
Balance at end of period	3,030
Allowance for loan losses for loans that are not PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	39,579	32,530
Loans charged-off	(1,447)	(403)
Recoveries of loans previously charged-off	676	632
Net (charge-offs) recoveries	(771)	229
Provision for loan losses	1,053	1,395
Balance at end of period	39,861	34,154
Allowance for loan losses for loans that are not PCI loans [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	5,518	6,003
Loans charged-off	(201)	(136)
Recoveries of loans previously charged-off	142	274
Provision for loan losses	(11)	(394)
Balance at end of period	5,448	5,747
Allowance for loan losses for loans that are not PCI loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	22,978	19,304
Recoveries of loans previously charged-off	152	94
Provision for loan losses	(883)	1,577
Balance at end of period	22,247	20,975
Allowance for loan losses for loans that are not PCI loans [Member] | Land, Development, Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	1,781	1,179
Loans charged-off	(31)
Recoveries of loans previously charged-off	83
Provision for loan losses	387	115
Balance at end of period	2,220	1,294
Allowance for loan losses for loans that are not PCI loans [Member] | Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	6,414	4,130
Loans charged-off	(664)	(7)
Recoveries of loans previously charged-off	155	6
Provision for loan losses	1,025	372
Balance at end of period	6,930	4,501
Allowance for loan losses for loans that are not PCI loans [Member] | Consumer and Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	2,888	1,914
Loans charged-off	(551)	(260)
Recoveries of loans previously charged-off	144	258
Provision for loan losses	535	(275)
Balance at end of period	3,016	1,637
Allowance for loan losses on PCI loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	191	295
Recoveries of loans previously charged-off		75
Net (charge-offs) recoveries		75
Provision for loan losses		(95)
Balance at end of period	191	275
Allowance for loan losses on PCI loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period		59
Balance at end of period		59
Allowance for loan losses on PCI loans [Member] | Land, Development, Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	177	222
Recoveries of loans previously charged-off		75
Provision for loan losses		(95)
Balance at end of period	177	202
Allowance for loan losses on PCI loans [Member] | Consumer and Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	14	14
Balance at end of period	$ 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	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Allowance for loan losses:
Individually evaluated for impairment	$ 2,475	$ 1,616
Collectively evaluated for impairment	37,386	37,963
Purchased credit impaired	191	191
Total ending allowance balance	40,052	39,770	$ 34,429	$ 32,825
Loans:
Individually evaluated for impairment	17,477	15,700
Collectively evaluated for impairment	8,179,425	8,163,140
Purchased credit impaired	149,456	158,971
Total ending loan balances	8,346,358	8,337,811
Residential Real Estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	324	331
Collectively evaluated for impairment	5,124	5,187
Total ending allowance balance	5,448	5,518
Loans:
Individually evaluated for impairment	5,657	6,234
Collectively evaluated for impairment	1,757,039	1,695,880
Purchased credit impaired	55,532	58,804
Total ending loan balances	1,818,228	1,760,918
Commercial Real Estate [Member]
Allowance for loan losses:
Individually evaluated for impairment	761	250
Collectively evaluated for impairment	21,486	22,728
Total ending allowance balance	22,247	22,978
Loans:
Individually evaluated for impairment	8,078	7,496
Collectively evaluated for impairment	4,392,505	4,446,602
Purchased credit impaired	80,792	87,336
Total ending loan balances	4,481,375	4,541,434
Land, Development, Construction [Member]
Allowance for loan losses:
Collectively evaluated for impairment	2,220	1,781
Purchased credit impaired	177	177
Total ending allowance balance	2,397	1,958
Loans:
Individually evaluated for impairment	116	117
Collectively evaluated for impairment	650,996	635,445
Purchased credit impaired	7,261	7,028
Total ending loan balances	658,373	642,590
Commercial and Industrial [Member]
Allowance for loan losses:
Individually evaluated for impairment	1,389	1,034
Collectively evaluated for impairment	5,541	5,380
Total ending allowance balance	6,930	6,414
Loans:
Individually evaluated for impairment	3,492	1,708
Collectively evaluated for impairment	1,172,474	1,181,672
Purchased credit impaired	5,662	5,594
Total ending loan balances	1,181,628	1,188,974
Consumer and Other [Member]
Allowance for loan losses:
Individually evaluated for impairment	1	1
Collectively evaluated for impairment	3,015	2,887
Purchased credit impaired	14	14
Total ending allowance balance	3,030	2,902
Loans:
Individually evaluated for impairment	134	145
Collectively evaluated for impairment	206,411	203,541
Purchased credit impaired	209	209
Total ending loan balances	$ 206,754	$ 203,895

Loans - Summary of Impaired Loa

Loans - Summary of Impaired Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Mortgage Loans On Real Estate [Line Items]
Total TDRs (these are included in impaired loans)	$ 9,893	$ 9,477
Impaired loans that are not TDRs	7,584	6,223
Total impaired loans	17,477	15,700
Performing TDRs [Member]
Mortgage Loans On Real Estate [Line Items]
Total TDRs (these are included in impaired loans)	8,801	8,475
Non-performing TDRs [Member]
Mortgage Loans On Real Estate [Line Items]
Total TDRs (these are included in impaired loans)	$ 1,092	$ 1,002

Loans - Additional Information

Loans - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Receivables [Abstract]
Loans modification, modified terms allowance period minimum	12 months
Loans modification, modified terms allowance period maximum	24 months
Provision for loan loss expense	$ 31	$ 11
Partial charge offs for troubled debt restructured	$ 8	11
Percentage of troubled debt restructured current pursuant to modified terms	89.00%
Non performing TDRs	$ 1,092
Percentage of troubled debt restructured not performing pursuant to their modified terms	11.00%
Loans modified as TDRs	$ 713	1,563
Loan loss provision modified as TDRs	0	0
Provision for loan loss expense within twelve months	0	2
Partial charge offs for troubled debt restructured	0	2
Reclassification from non-accretable difference	$ 7,199	$ 1,727

Loans - Troubled Debt Restructu

Loans - Troubled Debt Restructured Loans by Loans Type (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Modifications [Line Items]
TDRs	$ 9,893	$ 9,477
Total Real Estate Loans [Member]
Financing Receivable, Modifications [Line Items]
TDRs	8,498	8,755
Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	8,801	8,475
Accruing [Member] | Total Real Estate Loans [Member]
Financing Receivable, Modifications [Line Items]
TDRs	7,406	7,762
Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs	1,092	1,002
Non Accrual [Member] | Total Real Estate Loans [Member]
Financing Receivable, Modifications [Line Items]
TDRs	1,092	993
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
TDRs	5,996	6,234
Residential Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	5,507	5,848
Residential Real Estate [Member] | Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs	489	386
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
TDRs	2,386	2,403
Commercial Real Estate [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	1,823	1,837
Commercial Real Estate [Member] | Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs	563	566
Land, Development, Construction [Member]
Financing Receivable, Modifications [Line Items]
TDRs	116	118
Land, Development, Construction [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	76	77
Land, Development, Construction [Member] | Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs	40	41
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
TDRs	1,261	577
Commercial and Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	1,261	577
Consumer and Other [Member]
Financing Receivable, Modifications [Line Items]
TDRs	134	145
Consumer and Other [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs	$ 134	136
Consumer and Other [Member] | Non Accrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs		$ 9

Loans - Summary of Loans by Cla

Loans - Summary of Loans by Class Modified (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)SecurityLoan	Mar. 31, 2018USD ($)SecurityLoan
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan	1	1
Recorded investment | $	$ 122	$ 174
Commercial Real Estate [Member]
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan		1
Recorded investment | $		$ 174
Commercial and Industrial [Member]
Mortgage Loans On Real Estate [Line Items]
Number of loans | SecurityLoan	1
Recorded investment | $	$ 122

Loans - Summary of Loans Indivi

Loans - Summary of Loans Individually Evaluated for Impairment by Class of Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	$ 18,601	$ 16,593
Total impaired loans	17,477	15,700
Amount of allowance for loan losses allocated to impaired loans	2,475	1,616
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	3,030	3,608
Unpaid principal balance, With an allowance recorded	2,859	2,897
Recorded investment, With no related allowance	2,973	3,485
Recorded investment, With an allowance recorded	2,684	2,749
Total impaired loans	5,657	6,234
Amount of allowance for loan losses allocated to impaired loans	324	331
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	5,469	6,447
Unpaid principal balance, With an allowance recorded	3,423	1,593
Recorded investment, With no related allowance	4,799	5,906
Recorded investment, With an allowance recorded	3,279	1,590
Total impaired loans	8,078	7,496
Amount of allowance for loan losses allocated to impaired loans	761	250
Land, Development, Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	143	144
Recorded investment, With no related allowance	116	117
Total impaired loans	116	117
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	1,056	364
Unpaid principal balance, With an allowance recorded	2,481	1,378
Recorded investment, With no related allowance	1,045	353
Recorded investment, With an allowance recorded	2,447	1,355
Total impaired loans	3,492	1,708
Amount of allowance for loan losses allocated to impaired loans	1,389	1,034
Consumer and Other [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, With no allowance recorded	108	109
Unpaid principal balance, With an allowance recorded	32	53
Recorded investment, With no related allowance	107	108
Recorded investment, With an allowance recorded	27	37
Total impaired loans	134	145
Amount of allowance for loan losses allocated to impaired loans	$ 1	$ 1

Loans - Summary of Impairment b

Loans - Summary of Impairment by Class of Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	$ 16,589	$ 19,881
Interest income recognized during impairment	102	100
Total Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	13,849	16,661
Interest income recognized during impairment	88	92
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	5,945	8,133
Interest income recognized during impairment	62	77
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	7,787	8,264
Interest income recognized during impairment	25	12
Land, Development, Construction [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	117	264
Interest income recognized during impairment	1	3
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	2,600	3,025
Interest income recognized during impairment	12	6
Consumer and Other [Member]
Financing Receivable, Impaired [Line Items]
Average of impaired loans during the period	140	195
Interest income recognized during impairment	$ 2	$ 2

Loans - Summary of Nonperformin

Loans - Summary of Nonperforming Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Non-accrual loans	$ 35,181	$ 23,567
Loans past due over 90 days and still accruing interest	0	0
Total non-performing loans	$ 35,181	$ 23,567

Loans - Summary of Recorded Inv

Loans - Summary of Recorded Investment in Nonaccrual Loans and Loans Past Due Over 90 Days Still on Accrual by Class of Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	$ 35,181	$ 23,567
Loans past due over 90 days still accruing	0	0
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	12,888	11,488
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	10,259	8,445
Land, Development, Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	6,965	795
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	4,425	2,274
Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	$ 644	$ 565

Loans - Summary Aging of Record

Loans - Summary Aging of Recorded Investment in Past Due Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 8,196,902	$ 8,178,840
Total Past Due	34,635	36,502
Loans Not Past Due	8,127,086	8,118,771
Nonaccrual Loans	35,181	23,567
30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	25,899	21,094
60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,736	15,408
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	1,762,696	1,702,114
Total Past Due	13,782	11,360
Loans Not Past Due	1,736,026	1,679,266
Nonaccrual Loans	12,888	11,488
Residential Real Estate [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10,610	5,730
Residential Real Estate [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,172	5,631
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	4,400,583	4,454,098
Total Past Due	11,868	15,446
Loans Not Past Due	4,378,456	4,430,207
Nonaccrual Loans	10,259	8,445
Commercial Real Estate [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,012	10,840
Commercial Real Estate [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,856	4,607
Land, Development, Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	651,112	635,562
Total Past Due	4,115	4,683
Loans Not Past Due	640,032	630,084
Nonaccrual Loans	6,965	795
Land, Development, Construction [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,036	661
Land, Development, Construction [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	79	4,022
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	1,175,966	1,183,380
Total Past Due	3,900	3,681
Loans Not Past Due	1,167,641	1,177,425
Nonaccrual Loans	4,425	2,274
Commercial and Industrial [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,532	2,803
Commercial and Industrial [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	368	878
Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	206,545	203,686
Total Past Due	970	1,332
Loans Not Past Due	204,931	201,789
Nonaccrual Loans	644	565
Consumer and Other [Member] | 30 - 59 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	709	1,061
Consumer and Other [Member] | 60 - 89 days past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 261	$ 271

Loans - Risk Category of Loans

Loans - Risk Category of Loans by Class of Loans, Excluding Purchased Credit Impaired Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 1,762,696	$ 1,702,114
Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	206,545	203,686
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	7,871,931	7,831,100
Pass [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,696,127	1,633,810
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,210,370	4,246,687
Pass [Member] | Land, Development, Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	632,862	610,631
Pass [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,127,102	1,137,272
Pass [Member] | Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	205,470	202,701
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	239,921	264,172
Special Mention [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	38,771	41,522
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	144,831	160,981
Special Mention [Member] | Land, Development, Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	14,109	20,586
Special Mention [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	41,986	40,836
Special Mention [Member] | Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	224	247
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	85,050	83,568
Substandard [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	27,798	26,782
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	45,382	46,430
Substandard [Member] | Land, Development, Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,141	4,345
Substandard [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	6,878	5,272
Substandard [Member] | Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 851	$ 738

Loans - Investment in Residenti

Loans - Investment in Residential and Consumer Loans, Excluding Loans from Purchased Credit Impaired Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 1,762,696	$ 1,702,114
Residential Real Estate [Member] | Performing TDRs [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,749,808	1,690,626
Residential Real Estate [Member] | Non-performing TDRs [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	12,888	11,488
Consumer and Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	206,545	203,686
Consumer and Other [Member] | Performing TDRs [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	205,901	203,121
Consumer and Other [Member] | Non-performing TDRs [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 644	$ 565

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	Mar. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Contractually required principal and interest	$ 248,243	$ 267,815
Non-accretable difference	(28,865)	(38,602)
Cash flows expected to be collected	219,378	229,213
Accretable yield	(69,922)	(70,242)
Carrying value of acquired loans	149,456	158,971
Allowance for loan losses	(191)	(191)
Carrying value less allowance for loan losses	$ 149,265	$ 158,780

Loans - Summary of Changes in T

Loans - Summary of Changes in Total Contractually Required Principal and Interest Cash Payments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Contractually required principal and interest, beginning balance	$ 267,815
Non-accretable difference, beginning balance	(38,602)
Cash flows expected to be collected, beginning balance	229,213
Accretable yield, beginning balance	(70,242)
Carrying value of acquired loans, beginning balance	158,971
Contractually required principal and interest, ending balance	248,243
Non-accretable difference, ending balance	(28,865)
Cash flows expected to be collected, ending balance	219,378
Accretable yield, ending balance	(69,922)
Carrying value of acquired loans, ending balance	149,456
Contractually Required Principal and Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Contractually required principal and interest, beginning balance	267,815	$ 248,283
Effect of acquisitions		88,705
All other adjustments	(19,572)	(21,711)
Contractually required principal and interest, ending balance	248,243	315,277
Non-Accretable Difference [Member]
Financing Receivable, Recorded Investment [Line Items]
Non-accretable difference, beginning balance	(38,602)	(13,183)
Effect of acquisitions		(38,164)
All other adjustments	9,737	1,110
Non-accretable difference, ending balance	(28,865)	(50,237)
Cash Flows Expected to be Collected [Member]
Financing Receivable, Recorded Investment [Line Items]
Cash flows expected to be collected, beginning balance	229,213	235,100
Effect of acquisitions		50,541
All other adjustments	(9,835)	(20,601)
Cash flows expected to be collected, ending balance	219,378	265,040
Accretable Yield [Member]
Financing Receivable, Recorded Investment [Line Items]
Accretable yield, beginning balance	(70,242)	(70,942)
Effect of acquisitions		(6,278)
Income accretion	10,140	7,718
All other adjustments	(9,820)	(2,355)
Accretable yield, ending balance	(69,922)	(71,857)
Carry Value of Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Carrying value of acquired loans, beginning balance	158,971	164,158
Effect of acquisitions		44,263
Income accretion	10,140	7,718
All other adjustments	(19,655)	(22,956)
Carrying value of acquired loans, ending balance	$ 149,456	$ 193,183

Securities Sold Under Agreeme_3

Securities Sold Under Agreement to Repurchase - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Banking And Thrift [Abstract]
Securities sold under agreement to repurchase	$ 59,031	$ 57,772

Securities Sold Under Agreeme_4

Securities Sold Under Agreement to Repurchase - Summary of Repurchase Agreement (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets Sold Under Agreements To Repurchase [Line Items]
Market value of securities pledged	$ 63,053	$ 64,706
Securities sold under agreement to repurchase	$ 59,031	$ 57,772
Market value pledged as a % of borrowings	107.00%	112.00%
Mortgage Backed Securities [Member]
Assets Sold Under Agreements To Repurchase [Line Items]
Market value of securities pledged	$ 62,611	$ 64,269
Securities sold under agreement to repurchase	$ 58,829	$ 57,594
Market value pledged as a % of borrowings	106.00%	112.00%
Municipal Securities [Member]
Assets Sold Under Agreements To Repurchase [Line Items]
Market value of securities pledged	$ 442	$ 437
Securities sold under agreement to repurchase	$ 202	$ 178
Market value pledged as a % of borrowings	219.00%	246.00%

Business Combinations - Additio

Business Combinations - Additional Information (Detail) $ / shares in Units, $ in Thousands	Sep. 01, 2018USD ($)$ / shares	Jan. 01, 2018USD ($)$ / shares	Mar. 31, 2019USD ($)	Sep. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018	Sep. 30, 2017USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill on the acquisition			$ 802,880						$ 802,880
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			$ 0		$ 2,071
Goodwill on the acquisition		$ 114,228
Per share exchange ratio		0.89
Total purchase consideration		$ 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 loan acquired										14.30%
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]
Percentage of outstanding stock acquired		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			$ 0	$ 0		$ 5,789		$ 5,789
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
Total purchase consideration		$ 448,236
Loans at fair value		1,326,035
Estimated discount on loans acquired		$ 40,438
Estimated discount to outstanding principal balance		3.00%
Percentage of loan acquired										27.80%
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]
Percentage of outstanding stock acquired		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			$ 5,102
Goodwill on the acquisition	$ 197,648
Determination period for fair value estimates	1 year
Multiplied by the cash consideration each Platinum share is entitled to receive | $ / shares	$ 2.30
Per share exchange ratio	0.738
Total purchase consideration	$ 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 loan acquired										23.90%
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]
Percentage of outstanding stock acquired	100.00%

Business Combinations - Summary

Business Combinations - Summary of Purchase Price Calculation (Detail) $ / shares in Units, $ in Thousands	Sep. 01, 2018USD ($)$ / sharesshares	Jan. 01, 2018USD ($)$ / sharesshares
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 common shareholders		181,420
Fair value of 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
Total cash consideration		42,932
Total consideration paid to common shareholders		430,211
Fair value of stock options converted to CenterState stock options		18,025
Total purchase price		$ 448,236
Cash consideration each Harbor share is entitled to receive | $ / shares		$ 1.925
Total cash consideration, not including cash for fractional shares		$ 42,932
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
Total cash consideration	35,624
Total consideration paid to common shareholders	385,433
Total purchase price	$ 389,476
Cash consideration each Harbor share is entitled to receive | $ / shares	$ 2.30
Total cash consideration, not including cash for fractional shares	$ 35,624
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
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 Fair Value of Assets Purchased, Including Goodwill and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Sep. 01, 2018	Jan. 01, 2018
Assets:
Goodwill	$ 802,880	$ 802,880
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				11,670
Other assets				6,135
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				14,071
Other assets				2,536
Total assets acquired				2,379,069
FHLB and other stock				9,488
Other 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 real estate owned			257
Servicing asset			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 - 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
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
Book Balance [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		$ 706,979
Book Balance [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		1,366,473
Book Balance [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	$ 1,164,790
Book Balance [Member] | Residential Real Estate [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		148,342
Book Balance [Member] | Residential Real Estate [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		370,611
Book Balance [Member] | Residential Real Estate [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	284,505
Book Balance [Member] | Commercial Real Estate [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		375,377
Book Balance [Member] | Commercial Real Estate [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		636,517
Book Balance [Member] | Commercial Real Estate [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	567,506
Book Balance [Member] | Land, Development, Construction [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		58,530
Book Balance [Member] | Land, Development, Construction [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		149,547
Book Balance [Member] | Land, Development, Construction [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	181,128
Book Balance [Member] | Commercial and Industrial [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		104,811
Book Balance [Member] | Commercial and Industrial [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		113,818
Book Balance [Member] | Commercial and Industrial [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	88,308
Book Balance [Member] | Consumer and Other [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		1,770
Book Balance [Member] | Consumer and Other [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		41,660
Book Balance [Member] | Consumer and Other [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	26,221
Book Balance [Member] | Purchased Credit-Impaired [Member] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		18,149
Book Balance [Member] | Purchased Credit-Impaired [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		54,320
Book Balance [Member] | Purchased Credit-Impaired [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	17,122
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] | 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] | 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] | 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] | 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] | 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] | Sunshine Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		8,232
Fair Value [Member] | Purchased Credit-Impaired [Member] | HCBF Holding Company, Inc. [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans		$ 36,031
Fair Value [Member] | Purchased Credit-Impaired [Member] | Charter Financial Corporation [Member]
Business Acquisition [Line Items]
Book Balance and Fair Value of acquired loans	$ 11,432

Business Combinations - Pro-For

Business Combinations - Pro-Forma Financial Information And Actual Results of Acquisition (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)$ / shares
Business Combinations [Abstract]
Net interest income | $	$ 112,182
Net income available to common shareholders | $	$ 51,250
EPS - basic | $ / shares	$ 0.54
EPS - diluted | $ / shares	$ 0.53

Interest Rate Swap Derivative_2

Interest Rate Swap Derivatives - Additional Information (Detail) - Interest Rate Swap [Member] - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivative Instruments Notional And Fair Value [Line Items]
Derivative, Notional Amount	$ 6,194,936	$ 5,743,283
Collateral reserve for derivatives	$ 91,008	$ 28,345

Interest Rate Swap Derivative_3

Interest Rate Swap Derivatives - Summary Information about the Interest Rate Swap Derivative Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Fair value of interest rate swap derivatives (asset)	$ 130,122	$ 92,475
Fair value of interest rate swap derivatives (liability)	130,790	92,892
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional amount	$ 6,194,936	$ 5,743,283
Weighted average pay rate on interest-rate swaps	3.67%	3.64%
Weighted average receive rate on interest rate swaps	3.67%	3.64%
Weighted average maturity (years)	11 years	11 years
Fair value of interest rate swap derivatives (asset)	$ 130,122	$ 92,475
Fair value of interest rate swap derivatives (liability)	$ 130,790	$ 92,892

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating Lease, Asset	$ 21,143
Operating Lease, Liability	22,657
Cumulative adjustment pursuant to adoption of ASU 842	$ 1,464

Leases - Schedule of Lessee Lea

Leases - Schedule of Lessee Leases (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Amortization of ROU Assets - Finance Leases	$ 38
Interest on Lease Liabilities - Finance Leases	50
Operating Lease Cost (Cost resulting from lease payments)	1,287
Variable Lease Cost (Cost excluded from lease payments)	235
Total Lease Cost	1,610
Finance Lease - Operating Cash Flows	57
Finance Lease - Financing Cash Flows	91
Operating Lease - Operating Cash Flows (Fixed Payments)	1,241
Operating Lease - Operating Cash Flows (Liability Reduction)	1,181
New ROU Assets - Operating Leases	$ 21,351
Weighted Average Lease Term (Years) - Finance Leases	9 years 2 months 19 days
Weighted Average Lease Term (Years) - Operating Leases	7 years 7 months 24 days
Weighted Average Discount Rate - Finance Leases	5.95%
Weighted Average Discount Rate - Operating Leases	3.65%

Leases - Schedule of Maturity A

Leases - Schedule of Maturity Analysis of Undiscounted Cash Flows of Operating Lease Liabilities (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Operating lease payments due:
Within one year	$ 5,310
After one but within two years	4,257
After two but within three years	3,665
After three but within four years	2,599
After four years but within five years	2,136
After five years	7,896
Total undiscounted cash flows	25,863
Discount on cash flows	(3,206)
Total operating lease liabilities	$ 22,657

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Annual Rentals under All Leases (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2018	$ 6,524
2019	5,096
2020	4,411
2021	3,633
2022	2,558
Thereafter	11,088
Total minimum lease payments	$ 33,310

Leases - Schedule of Lessor Lea

Leases - Schedule of Lessor Leases (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating Lease Income from Lease Payments	$ 212
Direct Financing Lease Income	173
Total Lease Income	385
Net Investment in Direct Financing Leases	15,785
Maturity Analysis of Operating Lease Receivables
Maturity Analysis of Operating Lease Receivables, 0 - 12 Months	962
Maturity Analysis of Operating Lease Receivables, 13 - 24 Months	551
Maturity Analysis of Operating Lease Receivables, 25 - 36 Months	341
Maturity Analysis of Operating Lease Receivables, 37 - 48 Months	166
Maturity Analysis of Operating Lease Receivables, 48 - 60 Months	6
Maturity Analysis of Finance Lease Receivables
Maturity Analysis of Finance Lease Receivables, 0 - 12 Months	1,392
Maturity Analysis of Finance Lease Receivables, 13 - 24 Months	1,841
Maturity Analysis of Finance Lease Receivables, 25 - 36 Months	1,618
Maturity Analysis of Finance Lease Receivables, 37 - 48 Months	1,356
Maturity Analysis of Finance Lease Receivables, 48 - 60 Months	1,355
Maturity Analysis of Finance Lease Receivables, Over 60 Months	$ 12,543

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2019USD ($)	Mar. 31, 2019USD ($)Location	Apr. 01, 2019	Dec. 31, 2018USD ($)	Mar. 31, 2018USD ($)
Subsequent Event [Line Items]
Total assets		$ 12,587,637		$ 12,337,588	$ 10,347,996
Total deposits		9,747,025		$ 9,477,336
National Commerce Corporation [Member]
Subsequent Event [Line Items]
Merger and acquisition related expenses		$ 1,264
Number Of Service Banking Locations | Location		37
Total assets		$ 4,283,599
Total loans		3,360,938
Total deposits		$ 3,484,310
Subsequent Event | National Commerce Corporation [Member]
Subsequent Event [Line Items]
Per share exchange ratio			1.65
Total cash consideration	$ 825,464