FCB Financial 10-Q 7 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 01, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	FCB
Entity Registrant Name	FCB FINANCIAL HOLDINGS, INC.
Entity Central Index Key	1,476,651
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		46,827,114

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets:
Cash and due from banks	$ 76,633	$ 60,787
Interest-earning deposits in other banks	123,876	55,134
Cash and cash equivalents	200,509	115,921
Investment securities:
Available for sale debt securities, at fair value	2,275,703	2,030,696
Preferred stock and other equity securities, at fair value	71,015	90,107
Federal Home Loan Bank and other bank stock, at cost	65,847	56,881
Total investment securities	2,412,565	2,177,684
Loans held for sale	980	12,736
Loans:
Loans	9,316,808	7,977,784
Allowance for loan losses	(53,148)	(47,145)
Loans, net	9,263,660	7,930,639
Premises and equipment, net	42,645	36,144
Other real estate owned	10,534	14,906
Goodwill	139,529	81,204
Core deposit intangible	7,213	3,668
Deferred tax assets, net	40,743	27,043
Bank-owned life insurance	215,421	201,069
Other assets	99,557	76,065
Total assets	12,433,356	10,677,079
Transaction accounts:
Noninterest-bearing	1,577,741	1,236,685
Interest-bearing	4,225,178	4,830,525
Total transaction accounts	5,802,919	6,067,210
Time deposits	4,353,196	2,606,717
Total deposits	10,156,115	8,673,927
Borrowings (including FHLB advances of $750,000 and $670,000, respectively)	825,558	749,113
Other liabilities	74,197	74,867
Total liabilities	11,055,870	9,497,907
Commitments and contingencies (Note 13)
Stockholders’ Equity:
Additional paid-in capital	1,040,358	933,960
Retained earnings	439,233	313,645
Accumulated other comprehensive income (loss)	(24,782)	8,893
Treasury stock, at cost; 2,727,865; 2,694,489 Class A and 192,132; 192,132 Class B common shares	(77,373)	(77,373)
Total stockholders’ equity	1,377,486	1,179,172
Total liabilities and stockholders’ equity	12,433,356	10,677,079
Class A Common Stock
Stockholders’ Equity:
Common stock	50	47
Class B Non-voting Common Stock
Stockholders’ Equity:
Common stock	0	0
New loans
Loans:
Loans	8,629,402	7,661,385
Allowance for loan losses	(50,115)
Acquired loans
Loans:
Loans	687,406	$ 316,399
Allowance for loan losses	$ (1,167)

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
FHLB advances	$ 750,000	$ 670,000
Class A Common Stock
Common stock, par value (usd per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	49,537,170	47,065,593
Common stock, shares outstanding (in shares)	46,809,305	44,371,104
Treasury stock, shares (in shares)	2,727,865	2,694,489
Class B Non-voting Common Stock
Common stock, par value (usd per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	192,132	192,132
Common stock, shares outstanding (in shares)	0	0
Treasury stock, shares (in shares)	192,132	192,132

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest income:
Interest and fees on loans	$ 104,137	$ 76,465	$ 290,352	$ 214,570
Interest and dividends on investment securities	24,425	20,215	68,722	57,697
Other interest income	448	136	1,052	344
Total interest income	129,010	96,816	360,126	272,611
Interest expense:
Interest on deposits	33,300	17,134	85,397	46,277
Interest on borrowings	3,072	3,901	9,089	8,996
Total interest expense	36,372	21,035	94,486	55,273
Net interest income	92,638	75,781	265,640	217,338
Provision for loan losses	2,220	2,871	5,801	6,629
Net interest income after provision for loan losses	90,418	72,910	259,839	210,709
Noninterest income:
Service charges and fees	1,266	941	3,503	2,758
Loan and other fees	5,043	2,831	13,261	8,374
Bank-owned life insurance income	1,439	1,422	4,228	4,250
Income from resolution of acquired assets	202	466	603	1,548
Gain (loss) on sales of other real estate owned	(70)	(143)	43	(121)
Gain (loss) on investment securities	(184)	690	(1,472)	1,722
Other noninterest income	1,068	2,218	3,775	8,754
Total noninterest income	8,764	8,425	23,941	27,285
Noninterest expense:
Salaries and employee benefits	23,023	20,860	68,700	62,843
Occupancy and equipment expenses	4,012	3,283	11,872	10,016
Loan and other real estate related expenses	545	837	2,950	3,252
Professional services	3,929	1,390	7,335	4,250
Data processing and network	3,911	3,397	11,494	9,452
Regulatory assessments and insurance	2,564	2,330	7,257	6,691
Amortization of intangibles	371	256	1,035	768
Marketing and promotions	1,768	1,130	4,930	3,423
Other operating expenses	2,205	1,756	6,842	4,880
Total noninterest expense	42,328	35,239	122,415	105,575
Income before income tax expense	56,854	46,096	161,365	132,419
Income tax expense	13,374	13,936	35,052	26,189
Net income	$ 43,480	$ 32,160	$ 126,313	$ 106,230
Earnings per share:
Basic (usd per share)	$ 0.93	$ 0.74	$ 2.73	$ 2.49
Diluted (usd per share)	$ 0.89	$ 0.70	$ 2.61	$ 2.31
Weighted average shares outstanding:
Basic (shares)	46,693,707	43,333,947	46,213,176	42,580,426
Diluted (shares)	48,804,871	46,189,468	48,472,657	45,960,595

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 43,480	$ 32,160	$ 126,313	$ 106,230
Unrealized gains (losses) on available for sale debt securities:
Net unrealized holding gains (losses) on investment securities available for sale, net of taxes of $2,768, $369, $12,017, and $(12,131) respectively	(8,327)	(598)	(36,146)	19,519
Reclassification adjustment for realized (gains) losses on investment securities available for sale included in net income, net of taxes of $(418), $540, $(144), and $787, respectively	1,259	(869)	433	(1,267)
Cumulative adjustment from adoption of new accounting standards (1)	0	0	725	0
Net change in unrealized gains (losses) on available for sale debt securities	(7,068)	(1,467)	(34,988)	18,252
Unrealized gains (losses) on derivative instruments:
Net unrealized holding gains (losses) on derivative instruments, net of taxes of $(406), $0, $(437), and $0, respectively	1,220	0	1,313	0
Net change in unrealized gains (losses) on derivative instruments	1,220	0	1,313	0
Net change in accumulated other comprehensive income (loss)	(5,848)	(1,467)	(33,675)	18,252
Total comprehensive income (loss)	$ 37,632	$ 30,693	$ 92,638	$ 124,482

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net unrealized holding gains (losses) on investment securities available for sale, net of taxes of $2,768, $369, $12,017, and $(12,131) respectively	$ (2,768)	$ (369)	$ (12,017)	$ 12,131
Reclassification adjustment for realized (gains) losses on investment securities available for sale included in net income, net of taxes of $(418), $540, $(144), and $787, respectively	418	(540)	144	(787)
Tax on net unrealized holding gains (losses) on derivative instruments	$ (406)	$ 0	$ (437)	$ 0

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Additional Paid-in Capital	Retained Earnings (Deficit)	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Class A	Class ACommon Stock	Class B	Class BCommon Stock
Beginning Balance (in shares) at Dec. 31, 2016							40,969,097		197,950
Beginning Balance at Dec. 31, 2016	$ 982,441	$ 875,314	$ 188,451	$ (77,373)	$ (3,995)		$ 44		$ 0
Net income	106,230		106,230
Exchange of B shares to A shares (in shares)							197,950		(197,950)
Exchange of B shares to A shares							$ 0		$ 0
Stock-based compensation and warrant expense	5,970	5,970
Stock issued in connection with equity awards and warrants (in shares)							2,561,255
Stock issued in connection with equity awards and warrants	43,223	43,221					$ 2
Other	(43)	(43)
Other comprehensive income (loss)	18,252				18,252
Ending Balance, shares (in shares) at Sep. 30, 2017							43,728,302		0
Ending Balance at Sep. 30, 2017	1,156,073	924,462	294,681	(77,373)	14,257		$ 46		$ 0
Cumulative adjustment from adoption of new accounting standards (1)			(725)		725
Cumulative adjustment from adoption of new accounting standards (1) | ASU 2016-01			1,000
Cumulative adjustment from adoption of new accounting standards (1) | ASU 2018-02			(1,700)
Beginning Balance (in shares) at Dec. 31, 2017						44,371,104	44,371,104	0	0
Beginning Balance at Dec. 31, 2017	1,179,172	933,960	313,645	(77,373)	8,893		$ 47		$ 0
Net income	126,313		126,313
Stock issued in connection with acquisition, net of issuance cost (in shares)							1,754,362
Stock issued in connection with acquisition	94,122	94,120					$ 2
Stock-based compensation and warrant expense	6,635	6,635
Stock issued in connection with equity awards and warrants (in shares)							724,486
Stock issued in connection with equity awards and warrants	8,060	8,059					$ 1
Shares surrendered for tax withholding obligations (in shares)							(40,647)
Shares surrendered for tax withholding obligations	(2,066)	(2,066)
Other	(350)	(350)
Other comprehensive income (loss)	(33,675)
Other comprehensive income (loss) | ASU 2016-01 and 2018-02	(34,400)				(34,400)
Ending Balance, shares (in shares) at Sep. 30, 2018						46,809,305	46,809,305	0	0
Ending Balance at Sep. 30, 2018	$ 1,377,486	$ 1,040,358	$ 439,233	$ (77,373)	$ (24,782)		$ 50		$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows From Operating Activities:
Net income	$ 126,313	$ 106,230
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for loan losses	5,801	6,629
Amortization of intangible assets	1,035	768
Depreciation and amortization of premises and equipment	2,811	2,674
Accretion of discount on loans	(2,051)	(693)
Net amortization (accretion) of premium (discount) on investment securities	1,802	1,547
Net amortization (accretion) of premium (discount) on time deposits	(207)	0
Net amortization (accretion) on FHLB advances and other borrowings	0	(846)
Impairment of other real estate owned	1,097	437
Impairment of fixed assets HFS	110	0
(Gain) loss on available for sale debt securities	(355)	1,722
(Gain) loss on sale of loans	(660)	(3,835)
(Gain) loss on sale of other real estate owned	(43)	121
(Gain) loss on sale of premises and equipment	13	(7)
Unrealized (gain) loss on preferred stock and other equity securities	1,117	0
Stock-based compensation	6,635	5,970
Increase in cash surrender value of BOLI	(4,228)	(4,250)
Net change in operating assets and liabilities:
Net change in loans held for sale	1,641	8,353
Net change in other assets	(39)	(10,164)
Net change in other liabilities	7,017	25,094
Net cash provided by operating activities	148,519	136,306
Cash Flows From Investing Activities:
Purchase of equity securities	(42)	0
Purchase of available for sale debt securities	(635,501)	(656,982)
Sale of equity securities	18,016	0
Sales of available for sale debt securities	77,705	113,862
Paydown and maturities of available for sale debt securities	259,925	336,303
Purchase of FHLB and other bank stock	(95,966)	(121,995)
Sales of FHLB and other bank stock	90,441	111,813
Cash received in acquisition	16,656	0
Net change in loans	(919,001)	(1,094,190)
Purchase of loans	(7,382)	(2,782)
Proceeds from sale of loans	26,015	234,518
Proceeds from sale of other real estate owned	3,686	2,871
Purchase of premises and equipment	(7,064)	(1,790)
Proceeds from the sale of premises and equipment	1,054	34
Proceeds from life insurance	365	3,016
Net cash used in investing activities	(1,171,093)	(1,075,322)
Cash Flows From Financing Activities:
Net change in deposits	1,100,062	800,422
Net change in FHLB advances	8,596	195,750
Net change in repurchase agreements	(5,540)	(71,785)
Cash paid for withholding taxes on share based payments	(3,666)	0
Exercise of stock options and warrants	8,060	43,223
Other financing costs	(350)	(43)
Net cash provided by financing activities	1,107,162	967,567
Net Change in Cash and Cash Equivalents	84,588	28,551
Cash and Cash Equivalents at Beginning of Period	115,921	83,876
Cash and Cash Equivalents at End of Period	200,509	112,427
Supplemental Disclosures of Cash Flow Information:
Interest paid	92,427	55,177
Income taxes paid	24,159	6,122
Supplemental disclosure of noncash investing and financing activities:
Transfer/adjustments of loans to other real estate owned	266	1,800
Transfers from loans held for sale to portfolio loans	10,683	0
(Purchase) sale of investment securities settled in subsequent period, net	$ (63,756)	$ 6,214

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES General The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all information and notes to the consolidated financial statements necessary for a complete presentation of financial position, results of operations, comprehensive income and cash flows in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”) and should be read in conjunction with the audited consolidated financial statements and the notes thereto for FCB Financial Holdings, Inc. (the “Company”) previously filed with the SEC in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . In the opinion of management, all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation, have been included. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period. Nature of Operations The Company is a national bank holding company with two wholly-owned subsidiaries: (i) Florida Community Bank, N.A., a national bank (“Florida Community Bank” or the “Bank”); and (ii) Floridian Custody Services, Inc. ("Custody Services"). Florida Community Bank, headquartered in Weston, Florida, offers a comprehensive range of traditional banking products and services to individual and corporate customers through 51 banking centers located in Florida as of September 30, 2018 . Custody Services, headquartered in Davie, Florida, provides clearing and custodian services to deposit brokers and their clients. Principles of Consolidation The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, Custody Services and Florida Community Bank, and the Bank’s subsidiaries, which consist of a group of real estate holding companies. Intercompany transactions and balances have been eliminated in consolidation. Use of Estimates The Company’s financial reporting and accounting policies conform to U.S. GAAP. The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates subject to significant change include the allowance for loan losses, valuation of and accounting for acquired loans, the carrying value of OREO, the fair value of financial instruments, the valuation of goodwill and other intangible assets, acquisition-related fair value computations, stock-based compensation and deferred taxes. Recently Adopted Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)”, which superseded the revenue recognition requirements in Topic 605, Revenue Recognition, and most industry-specific revenue recognition guidance throughout the Accounting Standards Codification. Under ASU No. 2014-09, revenue should be recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying the guidance, an entity should 1) identify the contract(s) with a customer, 2) identify the performance obligations in the contract, 3) determine the transaction price, 4) allocate the transaction price to the performance obligations in the contract, and 5) recognize revenue when the entity satisfies a performance obligation. This guidance should be applied to all contracts with customers except those that are within the scope of other standards. This ASU became effective for the quarter ended March 31, 2018. The Company elected to adopt the new guidance under the modified retrospective approach. Since the Company's revenue is comprised primarily of net interest income from financial instruments that are within the scope of other standards, including loans and securities, the new guidance did not have a material impact upon adoption. In addition, the adoption of this guidance did not result in any material changes to the method of revenue recognition on the components of noninterest income. Accordingly, the adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In May 2016, the FASB issued ASU No. 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing.” The amendments in this ASU do not change the core principle of the guidance in Topic 606. Rather, the amendments in this ASU clarify the following two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance, while retaining the related principles for those areas. The amendments in this ASU affect the guidance in ASU 2014-09, “Revenue from Contracts with Customers (Topic 606)”. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In May 2016, the FASB issued ASU No. 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients.” The amendments in this ASU do not change the core principle of the guidance in Topic 606. Rather, the amendments in this ASU clarify the guidance on assessing collectability, presentation of sales taxes, noncash consideration, and completed contracts and contract modifications at transition. The amendments in this ASU affect the guidance in ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)". This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In January 2016, the FASB issued ASU No. 2016-01, “Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” which: • Requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. • Simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment. When a qualitative assessment indicates that impairment exists, an entity is required to measure the investment at fair value. • Eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet. • Requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes. • Requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. • Requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements. • Clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. An entity should apply the amendments by means of a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. The amendments related to equity securities without readily determinable fair values (including disclosure requirements) should be applied prospectively to equity investments that exist as of the date of adoption of the ASU. This ASU became effective the for the quarter ended March 31, 2018. As of January 1, 2018, the Company had equity securities in a net pre-tax unrealized gain position of $1.6 million for which $1.0 million , the tax effected balance, was reclassified from other comprehensive income to beginning retained earnings at adoption. In August 2016, the FASB issued ASU No. 2016-15, "Statement of cash flows (Topic 230): Classification of certain cash receipts and cash payments." The objective of this guidance is to reduce the diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows under Topic 230, Statement of Cash Flows, and other Topics. This ASU addresses the following eight specific cash flow issues: Debt prepayment or debt extinguishment costs; settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; contingent consideration payments made after a business combination; proceeds from the settlement of insurance claims; proceeds from the settlement of corporate-owned life insurance policies (COLIs) (including bank-owned life insurance policies (BOLIs)); distributions received from equity method investees; beneficial interests in securitization transactions; and separately identifiable cash flows and application of the predominance principle. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In October 2016, the FASB issued ASU No. 2016-16, "Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory." The objective of issuing this ASU is to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party. This prohibition on recognition is an exception to the principle of comprehensive recognition of current and deferred income taxes in GAAP. As such, the Board decided that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Consequently, the amendments in this guidance eliminate the exception for an intra-entity transfer of an asset other than inventory. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In November 2016, the FASB issued ASU No. 2016-18, "Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force)." The amendments in this ASU require that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in this ASU do not provide a definition of restricted cash or restricted cash equivalents. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In February 2017, the FASB issued ASU No. 2017-05, "Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets." The FASB is issuing this ASU to clarify the scope of Subtopic 610-20, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets, and to add guidance for partial sales of nonfinancial assets. The amendments in this ASU will require all entities to account for the derecognition of a business or nonprofit activity in accordance with Topic 810. The amendments also eliminate several accounting differences between transactions involving assets and transactions involving businesses. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In May 2017, the FASB issued ASU No. 2017-09, "Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting." This ASU provides clarity when applying the guidance in Topic 718, specifically relating to a modification of a share-based payment award. Entities should treat changes as modifications unless the fair value, vesting conditions, and classification of the modified awards are unchanged from the conditions immediately before the change. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In August 2017, the FASB issued ASU No. 2017-12, "Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities." This ASU improves the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements and makes certain targeted improvements to simplify the application of the hedge accounting guidance in current GAAP. The amendments in this update better align an entity's risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and presentation of hedge results. The Company early adopted ASU 2017-12 during the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In February 2018, the FASB issued ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” This ASU seeks to help entities reclassify certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017 (Tax Reform Act), enacted on December 22, 2017. ASU 2018-02 was issued in response to concerns regarding current guidance in GAAP that requires deferred tax liabilities and assets to be adjusted for the effect of a change in tax laws or rates with the effect included in income from continuing operations in the reporting period that includes the enactment date, even in situations in which the related income tax effects of items in accumulated other comprehensive income were originally recognized in other comprehensive income, rather than net income, and as a result the stranded tax effects would not reflect the appropriate tax rate. ASU 2018-02 allows an entity to make a reclassification from accumulated other comprehensive income to retained earnings for the stranded tax effects, which is the difference between the historical corporate income tax rate of 35.0% and the newly enacted corporate income tax rate of 21.0%. The amendments in this ASU are effective for fiscal years, and interim periods within those years, beginning after December 31, 2018; however, public business entities are allowed to early adopt ASU 2018-02 in any interim period for which the financial statements have not yet been issued. ASU 2018-02 may be applied either at the beginning of the period (annual or interim) of adoption or retrospectively to each of the period(s) in which the effect of the change in the U.S. federal corporate tax rate in the Tax Reform Act is recognized. As a result of the re-measurement of the Company's deferred tax assets following the enactment of the Tax Reform Act, accumulated other comprehensive income included $1.7 million of stranded tax effects at December 31, 2017. The Company early adopted ASU 2018-02 during the quarter ended March 31, 2018 and made the election to reclassify the stranded tax effects from accumulated other comprehensive income to retained earnings at the beginning of the period of adoption. Recently Issued Accounting Pronouncements In January 2018, the FASB issued ASU No. 2018-01, "Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842." This ASU provides an optional transition practical expedient to not evaluate under Topic 842, existing or expired land easements that were not previously accounted for as leases under the current leases guidance in Topic 840. An entity that elects this practical expedient should evaluate new or modified land easements under Topic 842 beginning at the date that the entity adopts Topic 842. An entity that does not elect this practical expedient should evaluate all existing or expired land easements in connection with the adoption of the new lease requirements in Topic 842 to assess whether they meet the definition of a lease. The amendments in this guidance affect the amendments in ASU 2016-02, which are not yet effective but may be early adopted. The effective date and transition requirements for the amendments are the same as the effective date and transition requirements in ASU 2016-02. An entity that early adopted Topic 842 should apply the amendments in this ASU upon issuance. Management does not intend to early adopt this guidance. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In June 2018, the FASB issued ASU 2018-07, "Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting." The amendments of this ASU expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. 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 are effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In July 2018, the FASB issued ASU 2018-11, "Leases (Topic 842): Targeted Improvements." The amendments of this ASU provide another transition method for the adoption of the new leases standard. Currently, entities are required to adopt the new leases standard using a modified retrospective transition method. The amendments of this ASU provide another transition method by allowing entities to initially apply the new leases standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Additionally, this ASU also provides lessors a practical expedient to not separate nonlease components from the associated lease component, similar to the expedient provided for lessees. The amendments related to separating components of a contract affect the amendments in ASU 2016-02, which are not yet effective but can be early adopted. For entities that have not adopted Topic 842 before the issuance of this ASU, the effective date and transition requirements for the amendments in this ASU related to separating components of a contract are the same as the effective date and transition requirements in ASU 2016-02. Management does not intend to early adopt this guidance. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In August 2018, the FASB issued ASU 2018-13, "Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement." The amendments of this ASU modify the disclosure requirements about recurring or nonrecurring fair value measurements required under Topic 820, Fair Value Measurement, and require additional disclosures related to unrealized gains and losses included in other comprehensive income. The amendments in this ASU are effective for all entities for fiscal years, and interim periods within those fiscal years, 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 ASU. An entity is permitted to early adopt any removed or modified disclosures upon issuance of this ASU and delay adoption of the additional disclosures until their effective date. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In August 2018, the FASB issued ASU 2018-15, "Intangibles - Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract." The amendments in this ASU align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The amendments in this ASU are effective for public business entities for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption of the amendments in this ASU is permitted, including adoption in any interim period, for all entities. The amendments in this ASU should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows.

Business Acquisitions

Business Acquisitions	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Business Acquisitions	BUSINESS ACQUISITIONS On March 1, 2018, the Company acquired 100% of the outstanding common stock of Floridian Community Holdings, Inc., ("Floridian") the parent company of Floridian Community Bank and Floridian Custody Services, Inc. Under the terms of the acquisition, each share of Floridian common stock was converted into 0.4584 shares of FCB Class A common stock at the effective date. A total of 1,754,362 shares of FCB Class A common stock were issued to holders of Floridian common stock. The Company also paid cash of $7 thousand for fractional shares resulting from the application of the exchange ratio. In addition, the Company incurred a liability of $5.2 million related to Floridian's outstanding stock options that were settled in cash subsequent to the acquisition. The Floridian acquisition will (i) expand the Company's business within demographically attractive markets in southeast Florida; (ii) increase the Company's core deposit base, an important funding source; and (iii) provide the opportunity to sell the Company's broad array of products to Floridians' client base, among other benefits. The results of operations were included in the Company's results beginning on March 1, 2018, the date of acquisition. The fair value of the common shares issued as part of the consideration paid for Floridian was determined using the closing price of the Company's common shares on February 28, 2018. Floridian had total assets of $506.8 million , total liabilities of $465.8 million and operated 5 full-service branches in South Florida as of March 1, 2018. Goodwill of $58.3 million was recognized in the transaction. None of the goodwill recognized is expected to be deductible for income tax purposes. The Company determined that the acquisition of Floridian constituted a business combination as defined by ASC Topic 805, “Business Combinations”. The acquisition was not considered to be a significant business combination. The assets acquired and liabilities assumed were recorded at their fair values on the date of acquisition. Fair values were determined in accordance with the guidance provided in ASC Topic 820, “Fair Value Measurements”. In many cases, the determination of fair value required management to make estimates about discount rates, future expected cash flows, market conditions and other future events that are highly subjective in nature and subject to change. The Company utilized the assistance of third-party advisors in the determination of fair value for loans, deposits, other real estate owned and deferred tax assets acquired. The Company may incur losses on the acquired loans that are materially different from losses the Company originally projected. The Company recorded adjustments to the preliminary fair value estimates in the reporting period in which the adjustments were determined. During the nine months ended September 30, 2018, the Company recorded adjustments to the preliminary fair value estimates resulting in a decrease in assets acquired of $858 thousand , liabilities assumed of $1.1 million , and goodwill of $255 thousand . The adjustments were primarily related to a reduction in the estimated fair value of an assumed liability and other receivables. As of September 30, 2018, the Company has finalized its valuation of the Floridian acquisition. The following table presents a summary of the assets acquired and liabilities assumed in the Floridian acquisition recorded at fair value: Acquisition Date Fair Value Measurement Period Adjustments Adjusted Acquisition Date Fair Value (Dollars in thousands) Consideration transferred: Common stock issued $ 94,122 $ — $ 94,122 Liability incurred related to settlement of outstanding stock options 5,198 — 5,198 Total consideration transferred 99,320 — 99,320 Fair value of assets acquired: Cash and cash equivalents 16,699 (43 ) 16,656 Investment securities 38,772 — 38,772 Loans 425,894 — 425,894 Other real estate owned 113 (2 ) 111 Core deposit intangible 4,580 — 4,580 Fixed assets 3,425 — 3,425 Deferred tax asset, net 5,043 (239 ) 4,804 Bank-owned life insurance 10,489 — 10,489 Other assets 2,678 (574 ) 2,104 Total identifiable assets acquired 507,693 (858 ) 506,835 Fair value of liabilities assumed: Deposits 382,333 — 382,333 FHLB advances and other borrowings 73,389 — 73,389 Other liabilities 11,231 (1,113 ) 10,118 Total liabilities assumed 466,953 (1,113 ) 465,840 Fair value of net assets acquired 40,740 255 40,995 Goodwill resulting from acquisition $ 58,580 $ (255 ) $ 58,325 On July 24, 2018, the Company announced the entry into a definitive merger agreement under which it will be acquired by Columbus, Georgia based Synovus Financial Corp. ("Synovus"). Under the terms of the merger agreement, the Company’s shareholders will receive a fixed ratio of 1.055 shares of Synovus common stock for each common share of the Company in an all-stock transaction. The merger agreement has been unanimously approved by both companies’ Boards of Directors and is subject to customary closing conditions, including approval by the shareholders of both companies and by state and federal bank regulators. The Company and Synovus filed notices and applications to obtain the necessary regulatory approvals on August 22, 2018. The Georgia Department of Banking and Finance approvals were received on September 25, 2018. On October 9, 2018, an action captioned Stephen Bushansky v. FCB Financial Holdings, Inc. et al., Case 1:18-cv-62399-BB, was filed in the United States District Court, Southern District of Florida on behalf of a purported class of FCB’s stockholders against FCB and its current directors. This complaint alleges violations of Sections 14(a) and 20(a) of the Exchange Act. The action seeks, among other things, to enjoin the defendants from consummating the merger until additional information is disclosed to FCB’s stockholders in advance of the FCB special meeting or to rescind the merger or recover damages to the extent the merger is completed. On October 11, 2018, an action captioned Paul Parshall v. FCB Financial Holdings, Inc. et al., Case 1:18-cv-01570-LPS, was filed in the United States District Court for the District of Delaware on behalf of a purported class of FCB’s stockholders against FCB, its current directors, Synovus and Merger Sub, alleging violations of Sections 14(a) and 20(a) of the Exchange Act. The action seeks, among other things, to cause defendants to disseminate adequate disclosures, to enjoin defendants from consummating the merger, and to rescind the merger or recover damages to the extent the merger is completed. The court has not acted on either of these complaints, and no relief has been granted as of this time.

Investment Securities

Investment Securities	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Investment Securities	INVESTMENT SECURITIES The amortized cost, gross unrealized gains and losses and approximate fair values of available for sale debt securities are as follows: Amortized Cost Unrealized Fair Value September 30, 2018 Gains Losses (Dollars in thousands) Available for sale debt securities: U.S. Government agencies and sponsored enterprises obligations $ 86,941 $ — $ 2,709 $ 84,232 U.S. Government agencies and sponsored enterprises mortgage-backed securities 627,668 9 23,519 604,158 State and municipal obligations 24,485 66 1,669 22,882 Asset-backed securities 780,250 330 2,258 778,322 Corporate bonds and other debt securities 791,130 7,609 12,630 786,109 Total available for sale debt securities $ 2,310,474 $ 8,014 $ 42,785 $ 2,275,703 Amortized Cost Unrealized Fair Value December 31, 2017 Gains Losses (Dollars in thousands) Available for sale debt securities: (1) U.S. Government agencies and sponsored enterprises obligations $ 43,471 $ 38 $ 671 $ 42,838 U.S. Government agencies and sponsored enterprises mortgage-backed securities 600,310 1,716 6,789 595,237 State and municipal obligations 26,766 125 719 26,172 Asset-backed securities 608,340 2,306 100 610,546 Corporate bonds and other debt securities 738,994 18,222 1,313 755,903 Total available for sale debt securities $ 2,017,881 $ 22,407 $ 9,592 $ 2,030,696 (1) To allow for improved comparability, prior year presentation has been modified to remove preferred stock and other equity securities in connection with the adoption of ASU 2016-01. As part of the Company’s liquidity management strategy, the Company pledges loans and securities to secure borrowings from the Federal Home Loan Bank of Atlanta ("FHLB") and the Federal Reserve Bank of Atlanta ("FRB"). The Company also pledges securities to collateralize public deposits, repurchase agreements and interest rate swaps. The carrying value of all pledged securities totaled $950.4 million and $834.9 million at September 30, 2018 and December 31, 2017 , respectively. The amortized cost and estimated fair value of available for sale debt securities, by contractual maturity, are as follows: September 30, 2018 Amortized Cost Fair Value (Dollars in thousands) Available for sale debt securities: Due in one year or less $ 57,430 $ 57,475 Due after one year through five years 290,655 287,076 Due after five years through ten years 138,696 135,574 Due after ten years 328,834 328,866 U.S. Government agencies and sponsored enterprises obligations, mortgage-backed securities and asset-backed securities 1,494,859 1,466,712 Total available for sale debt securities $ 2,310,474 $ 2,275,703 For purposes of the maturity table, U.S Government agencies and sponsored enterprises obligations, agency mortgage-backed securities and asset-backed securities, the principal of which are repaid periodically, are presented as a single amount. The expected lives of these securities will differ from contractual maturities because borrowers may have the right to prepay the underlying loans with or without prepayment penalties. The following tables present the estimated fair values and gross unrealized losses on available for sale debt securities, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position as of the periods presented: Less than 12 Months 12 Months or More Total September 30, 2018 Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss (Dollars in thousands) Available for sale debt securities: U.S. Government agencies and sponsored enterprises obligations $ 51,529 $ 906 $ 32,703 $ 1,803 $ 84,232 $ 2,709 U.S. Government agencies and sponsored enterprises mortgage-backed securities 279,436 8,128 300,994 15,391 580,430 23,519 State and municipal obligations — — 20,772 1,669 20,772 1,669 Asset-backed securities 348,117 2,196 7,002 62 355,119 2,258 Corporate bonds and other debt securities 391,610 8,486 91,574 4,144 483,184 12,630 Total available for sale debt securities $ 1,070,692 $ 19,716 $ 453,045 $ 23,069 $ 1,523,737 $ 42,785 Less than 12 Months 12 Months or More Total December 31, 2017 Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss (Dollars in thousands) Available for sale debt securities: (1) U.S. Government agencies and sponsored enterprises obligations $ 31,518 $ 268 $ 7,157 $ 403 $ 38,675 $ 671 U.S. Government agencies and sponsored enterprises mortgage-backed securities 207,735 1,836 175,810 4,953 383,545 6,789 State and municipal obligations 192 2 23,813 717 24,005 719 Asset-backed securities 36,542 100 — — 36,542 100 Corporate bonds and other debt securities 186,052 1,240 10,842 73 196,894 1,313 Total available for sale debt securities $ 462,039 $ 3,446 $ 217,622 $ 6,146 $ 679,661 $ 9,592 (1) To allow for improved comparability, prior year presentation has been modified to remove preferred stock and other equity securities in connection with the adoption of ASU 2016-01. At September 30, 2018 , the Company’s security portfolio consisted of 355 securities, of which 245 securities were in an unrealized loss position. A total of 137 were in an unrealized loss position for less than 12 months . The unrealized losses for these securities resulted primarily from changes in interest rates and spreads. The Company monitors its investment securities for other-than-temporary-impairment ("OTTI"). Impairment is evaluated on an individual security basis considering numerous factors, and their relative significance. The Company has evaluated the nature of unrealized losses in the investment securities portfolio to determine if OTTI exists. The unrealized losses relate to changes in market interest rates and market conditions that do not represent credit-related impairments. Furthermore, the Company does not intend to sell nor is it more likely than not that it will be required to sell these investments before the recovery of their amortized cost basis. Management has completed an assessment of each security in an unrealized loss position for credit impairment and has determined that no individual security was other-than-temporarily impaired at September 30, 2018 . The following describes the basis under which the Company has evaluated OTTI: U.S. Government Agencies and Sponsored Enterprises Obligations and Agency Mortgage-Backed Securities (“MBS”): The unrealized losses associated with U.S. Government agencies and sponsored enterprises obligations and agency MBS are primarily driven by changes in interest rates. These securities have either an explicit or implicit U.S. government guarantee. Asset-Backed Securities and Corporate Bonds & Other Debt Securities: Securities were generally underwritten in accordance with the Company’s investment standards prior to the decision to purchase, without relying on a bond issuer’s guarantee in making the investment decision. These investments were investment grade as of September 30, 2018 and December 31, 2017 and will continue to be monitored as part of the Company’s ongoing impairment analysis, but are expected to perform in accordance with their terms. Preferred Stock and Other Equity Securities: The unrealized losses associated with preferred stock and other equity securities in large U.S. financial institutions are primarily driven by changes in interest rates and spreads. These securities were generally underwritten in accordance with the Company’s investment standards prior to the decision to purchase. Gross realized gains and losses on the sale of available for sale debt securities are shown below. The cost of securities sold is based on the specific identification method. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (Dollars in thousands) Gross realized gains $ 2 $ 1,251 $ 147 $ 1,945 Gross realized losses (1,248 ) (1,533 ) (1,254 ) (2,739 ) Net realized gains (losses) $ (1,246 ) $ (282 ) $ (1,107 ) $ (794 ) The Company adopted ASU 2016-01 as of January 1, 2018. This guidance requires investments in equity securities with readily determinable fair values to be measured at fair value, with changes in the fair value recognized as a component of noninterest income in the Company's Consolidated Statements of Income. The Company recognized $1.1 million of unrealized gain and $1.1 million of unrealized loss in noninterest income during the three and nine months ended September 30, 2018 , respectively, related to equity securities still held at the end of the period.

Loans, Net

Loans, Net	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Loans, Net	LOANS, NET The Company’s loan portfolio consists of New and Acquired loans. The Company classifies originated loans and purchased loans not acquired through business combinations that did not show evidence of credit deterioration as New loans. The Company classifies loans acquired through business combinations and purchased loans acquired outside of a business combination that show evidence of credit deterioration as Acquired loans. Loans acquired with deteriorated credit quality since origination are accounted for under ASC 310-30, unless specifically excluded from the scope of ASC 310-30. The remaining portfolio of Acquired loans and those loans excluded from the scope of ASC 310-30 are accounted for under ASC 310-20 and are classified as Non-ASC 310-30 loans. The following tables summarize the Company’s loans by portfolio and segment as of the periods presented, net of deferred fees, costs, premiums and discounts: September 30, 2018 ASC 310-30 Loans Non-ASC 310-30 Loans New Loans (1) Total (Dollars in thousands) Real estate loans: Commercial real estate $ 133,778 $ 104,364 $ 2,528,748 $ 2,766,890 Owner-occupied commercial real estate — 81,408 1,134,793 1,216,201 1-4 single family residential 32,240 148,659 2,245,139 2,426,038 Construction, land and development 28,590 36,881 754,972 820,443 Home equity loans and lines of credit — 40,131 59,729 99,860 Total real estate loans 194,608 411,443 6,723,381 7,329,432 Other loans: Commercial and industrial 19,503 46,643 1,902,045 1,968,191 Consumer 1,259 13,950 3,976 19,185 Total other loans 20,762 60,593 1,906,021 1,987,376 Total loans held in portfolio $ 215,370 $ 472,036 $ 8,629,402 $ 9,316,808 Allowance for loan losses (53,148 ) Loans held in portfolio, net $ 9,263,660 December 31, 2017 ASC 310-30 Loans Non-ASC 310-30 Loans New Loans (1) Total (Dollars in thousands) Real estate loans: Commercial real estate $ 104,335 $ 37,736 $ 2,103,788 $ 2,245,859 Owner-occupied commercial real estate — 16,100 987,781 1,003,881 1-4 single family residential 27,513 57,695 2,185,362 2,270,570 Construction, land and development 13,167 5,889 684,462 703,518 Home equity loans and lines of credit — 34,589 59,636 94,225 Total real estate loans 145,015 152,009 6,021,029 6,318,053 Other loans: Commercial and industrial 12,631 5,062 1,634,372 1,652,065 Consumer 1,423 259 5,984 7,666 Total other loans 14,054 5,321 1,640,356 1,659,731 Total loans held in portfolio $ 159,069 $ 157,330 $ 7,661,385 $ 7,977,784 Allowance for loan losses (47,145 ) Loans held in portfolio, net $ 7,930,639 (1) Balance includes $(9.2) million and $(6.6) million of net deferred fees, costs, and premium and discount as of September 30, 2018 and December 31, 2017 , respectively. At September 30, 2018 and December 31, 2017 , the unpaid principal balances of ASC 310-30 loans were $274.3 million and $183.9 million , respectively. At September 30, 2018 and December 31, 2017 , the Company had pledged loans as collateral for FHLB advances of $3.44 billion and $3.36 billion , respectively. The recorded investment of consumer mortgage loans, secured by 1-4 family residential real estate properties, for which formal foreclosure proceedings are in process as of September 30, 2018 totaled $4.2 million . The Company held $288.5 million and $289.1 million of syndicated national loans as of September 30, 2018 and December 31, 2017 , respectively. During the three months ended September 30, 2018 , the Company purchased no loans from third parties. During the nine months ended September 30, 2018 , the Company purchased approximately $7.4 million of loans from third parties. During the three and nine months ended September 30, 2017 , the Company purchased $2.8 million loans from third parties. During the three and nine months ended September 30, 2018 , the Company sold approximately $6.2 million and $26.0 million of held-to-maturity portfolio loans to third parties, respectively. During the three and nine months ended September 30, 2017 , the Company sold approximately $73.4 million and $232.3 million of held-to-maturity portfolio loans to third parties, respectively. The accretable discount on ASC 310-30 loans represents the amount by which the undiscounted expected cash flows on such loans exceed their carrying value. The change in expected cash flows for certain ASC 310-30 loan pools resulted in the reclassification of $3,417 thousand and $(2.7) million between non-accretable and accretable discount during the nine months ended September 30, 2018 and 2017 , respectively. Changes in accretable discount for ASC 310-30 loans for the nine months ended September 30, 2018 and 2017 , were as follows: Nine Months Ended September 30, 2018 2017 (Dollars in thousands) Balance at January 1, $ 41,162 $ 60,990 Additions to accretable discount from FLCB acquisition 14,393 — Accretion (10,857 ) (13,965 ) Reclassifications from (to) non-accretable difference 3,417 (2,747 ) Balance at September 30, $ 48,115 $ 44,278

Allowance for Loan Losses

Allowance for Loan Losses	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Allowance for Loan Losses	ALLOWANCE FOR LOAN LOSSES The Company’s accounting method for loans and the corresponding allowance for loan losses (“ALL”) differs depending on whether the loans are New or Acquired. The Company assesses and monitors credit risk and portfolio performance using distinct methodologies for Acquired loans, both ASC 310-30 Loans and Non-ASC 310-30 Loans, and New loans. Within each of these portfolios, the Company further disaggregates the portfolios into the following segments: Commercial real estate, Owner-occupied commercial real estate, 1-4 single family residential, Construction, land and development, Home equity loans and lines of credit, Commercial and industrial and Consumer. The ALL reflects management’s estimate of probable credit losses inherent in each of the segments. During the second quarter 2018, the Company released an unallocated allowance for loan loss of $1.5 million , which was recorded in prior year in response to Hurricane Irma. The following tables present information related to the ALL for the periods presented: Commercial Real Estate Owner- Occupied Commercial Real Estate 1-4 Single Family Residential Construction, Land and Development Home Equity Loans and Lines of Credit Commercial and Industrial Consumer Total (Dollars in thousands) Balance at July 1, 2018 $ 15,381 $ 3,946 $ 7,310 $ 4,076 $ 704 $ 18,934 $ 219 $ 50,570 Provision (credit) for ASC 310-30 loans (26 ) (3 ) 14 (115 ) — (66 ) (16 ) (212 ) Provision (credit) for non-ASC 310-30 loans (8 ) (3 ) (35 ) 71 2 129 — 156 Provision (credit) for New loans 560 (141 ) (333 ) 1,228 (24 ) 994 (8 ) 2,276 Provision (credit) for Unallocated — — — — — — — — Total provision 526 (147 ) (354 ) 1,184 (22 ) 1,057 (24 ) 2,220 Charge-offs for ASC 310-30 loans (1 ) — (22 ) — — — (4 ) (27 ) Charge-offs for non-ASC 310-30 loans (118 ) — — — — — — (118 ) Charge-offs for New loans — — — — — — — — Total charge-offs (119 ) — (22 ) — — — (4 ) (145 ) Recoveries for ASC 310-30 loans 366 3 1 93 — 7 — 470 Recoveries for non-ASC 310-30 loans — — 23 — — — — 23 Recoveries for New loans — 9 — — — — — 9 Total recoveries 366 12 24 93 — 7 — 502 Ending ALL balance ASC 310-30 loans 1,556 — 8 103 — 80 119 1,866 Non-ASC 310-30 loans 188 51 144 130 204 447 3 1,167 New loans 14,410 3,760 6,806 5,121 478 19,471 69 50,115 Unallocated — — — — — — — — Balance at September 30, 2018 $ 16,154 $ 3,811 $ 6,958 $ 5,354 $ 682 $ 19,998 $ 191 $ 53,148 Commercial Real Estate Owner- Occupied Commercial Real Estate 1-4 Single Family Residential Construction, Land and Development Home Equity Loans and Lines of Credit Commercial and Industrial Consumer Total (Dollars in thousands) Balance at July 1, 2017 $ 12,155 $ 3,286 $ 8,749 $ 4,713 $ 884 $ 11,296 $ 251 $ 41,334 Provision (credit) for ASC 310-30 loans (41 ) — — (38 ) — (38 ) (8 ) (125 ) Provision (credit) for non-ASC 310-30 loans 30 (1 ) (49 ) (2 ) (227 ) (56 ) 1 (304 ) Provision (credit) for New loans 943 342 (335 ) (113 ) 42 933 (12 ) 1,800 Provision (credit) for Unallocated — — — — — — — 1,500 Total provision 932 341 (384 ) (153 ) (185 ) 839 (19 ) 2,871 Charge-offs for ASC 310-30 loans — — — — — — — — Charge-offs for non-ASC 310-30 loans (30 ) — (9 ) — — (3 ) — (42 ) Charge-offs for New loans — — — — (3 ) — — (3 ) Total charge-offs (30 ) — (9 ) — (3 ) (3 ) — (45 ) Recoveries for ASC 310-30 loans 27 — — — — 70 — 97 Recoveries for non-ASC 310-30 loans — — 30 — — 4 — 34 Recoveries for New loans — — — — — — — — Total recoveries 27 — 30 — — 74 — 131 Ending ALL balance ASC 310-30 loans 1,664 — 25 147 — 200 152 2,188 Non-ASC 310-30 loans 331 64 214 36 224 311 7 1,187 New loans 11,089 3,563 8,147 4,377 472 11,695 73 39,416 Unallocated — — — — — — — 1,500 Balance at September 30, 2017 $ 13,084 $ 3,627 $ 8,386 $ 4,560 $ 696 $ 12,206 $ 232 $ 44,291 Commercial Real Estate Owner- Occupied Commercial Real Estate 1-4 Single Family Residential Construction, Land and Development Home Equity Loans and Lines of Credit Commercial and Industrial Consumer Total (Dollars in thousands) Balance at January 1, 2018 $ 13,870 $ 3,365 $ 7,978 $ 4,345 $ 674 $ 15,141 $ 272 $ 47,145 Provision (credit) for ASC 310-30 loans (102 ) (3 ) (15 ) (149 ) — (53 ) (15 ) (337 ) Provision (credit) for non-ASC 310-30 loans (32 ) (4 ) (62 ) 94 5 170 (3 ) 168 Provision (credit) for New loans 2,315 441 (963 ) 957 3 4,769 (52 ) 7,470 Provision (credit) for Unallocated — — — — — — — (1,500 ) Total provision 2,181 434 (1,040 ) 902 8 4,886 (70 ) 5,801 Charge-offs for ASC 310-30 loans (156 ) — (22 ) — — (17 ) (11 ) (206 ) Charge-offs for non-ASC 310-30 loans (118 ) — — — — (36 ) — (154 ) Charge-offs for New loans — — — — — — — — Total charge-offs (274 ) — (22 ) — — (53 ) (11 ) (360 ) Recoveries for ASC 310-30 loans 366 3 19 106 — 24 — 518 Recoveries for non-ASC 310-30 loans — — 23 — — — — 23 Recoveries for New loans 11 9 — — — — — 20 Total recoveries 377 12 42 106 — 24 — 561 Ending ALL balance ASC 310-30 loans 1,556 — 8 103 — 80 119 1,866 Non-ASC 310-30 loans 188 51 144 130 204 447 3 1,167 New loans 14,410 3,760 6,806 5,121 478 19,471 69 50,115 Unallocated — — — — — — — — Balance at September 30, 2018 $ 16,154 $ 3,811 $ 6,958 $ 5,354 $ 682 $ 19,998 $ 191 $ 53,148 Commercial Real Estate Owner- Occupied Commercial Real Estate 1-4 Single Family Residential Construction, Land and Development Home Equity Loans and Lines of Credit Commercial and Industrial Consumer Total (Dollars in thousands) Balance at January 1, 2017 $ 10,123 $ 2,597 $ 7,379 $ 4,677 $ 648 $ 12,245 $ 228 37,897 Provision (credit) for ASC 310-30 loans (623 ) — 31 (49 ) — (118 ) (92 ) (851 ) Provision (credit) for non-ASC 310-30 loans (15 ) 3 (48 ) (11 ) (12 ) (66 ) (28 ) (177 ) Provision (credit) for New loans 3,728 1,027 1,098 (14 ) 70 253 (5 ) 6,157 Provision (credit) for Unallocated — — — — — — — 1,500 Total provision 3,090 1,030 1,081 (74 ) 58 69 (125 ) 6,629 Charge-offs for ASC 310-30 loans (9 ) — (35 ) (43 ) — (29 ) — (116 ) Charge-offs for non-ASC 310-30 loans (30 ) — (69 ) — (7 ) (3 ) — (109 ) Charge-offs for New loans (131 ) — — — (3 ) (150 ) — (284 ) Total charge-offs (170 ) — (104 ) (43 ) (10 ) (182 ) — (509 ) Recoveries for ASC 310-30 loans 41 — — — — 70 100 211 Recoveries for non-ASC 310-30 loans — — 30 — — 4 29 63 Recoveries for New loans — — — — — — — — Total recoveries 41 — 30 — — 74 129 274 Ending ALL balance ASC 310-30 loans 1,664 — 25 147 — 200 152 2,188 Non-ASC 310-30 loans 331 64 214 36 224 311 7 1,187 New loans 11,089 3,563 8,147 4,377 472 11,695 73 39,416 Unallocated — — — — — — — 1,500 Balance at September 30, 2017 $ 13,084 $ 3,627 $ 8,386 $ 4,560 $ 696 $ 12,206 $ 232 $ 44,291 Credit Quality Indicators In evaluating credit risk, the Company looks at multiple factors; however, management considers delinquency status to be the most meaningful indicator of the credit quality of 1-4 single family residential, home equity loans and lines of credit and consumer loans. Delinquency statistics are updated at least monthly. Internal risk ratings are considered the most meaningful indicator of credit quality for Non-ASC 310-30 and New commercial, construction, land and development and commercial real estate loans. Internal risk ratings are updated on a continuous basis. The following tables present an aging analysis of the recorded investment for delinquent loans by portfolio and segment (excluding loans accounted for under ASC 310-30): Accruing September 30, 2018 30 to 59 Days Past Due 60 to 89 Days Past Due 90 Days or More Past Due Non- Accrual Total (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ 7 $ — $ 460 $ 467 Owner-occupied commercial real estate — 827 — 2,440 3,267 1-4 single family residential 1,993 334 — 4,157 6,484 Construction, land and development — — — — — Home equity loans and lines of credit — — — 126 126 Total real estate loans 1,993 1,168 — 7,183 10,344 Other loans: Commercial and industrial 212 152 — 155 519 Consumer 24 — — — 24 Total other loans 236 152 — 155 543 Total new loans $ 2,229 $ 1,320 $ — $ 7,338 $ 10,887 Acquired loans: Real estate loans: Commercial real estate $ — $ — $ — $ 3,615 $ 3,615 Owner-occupied commercial real estate — — — 486 486 1-4 single family residential — 96 — 1,677 1,773 Construction, land and development — — — — — Home equity loans and lines of credit 716 — — 2,543 3,259 Total real estate loans 716 96 — 8,321 9,133 Other loans: Commercial and industrial 64 24 — 2,816 2,904 Consumer — — — — — Total other loans 64 24 — 2,816 2,904 Total acquired loans $ 780 $ 120 $ — $ 11,137 $ 12,037 Accruing December 31, 2017 30 to 59 Days Past Due 60 to 89 Days Past Due 90 Days or More Past Due Non- Accrual Total (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ 324 $ — $ — $ — $ 324 Owner-occupied commercial real estate 843 150 — — 993 1-4 single family residential 1,179 1,310 — 3,167 5,656 Construction, land and development — — — — — Home equity loans and lines of credit — — — 126 126 Total real estate loans 2,346 1,460 — 3,293 7,099 Other loans: Commercial and industrial 4,980 2,167 — — 7,147 Consumer — — — — — Total other loans 4,980 2,167 — — 7,147 Total new loans $ 7,326 $ 3,627 $ — $ 3,293 $ 14,246 Acquired Loans: Real estate loans: Commercial real estate $ 360 $ — $ — $ 3,893 $ 4,253 Owner-occupied commercial real estate 290 — — 494 784 1-4 single family residential 892 44 — 1,331 2,267 Construction, land and development — — — — — Home equity loans and lines of credit 1,128 — — 1,720 2,848 Total real estate loans 2,670 44 — 7,438 10,152 Other loans: Commercial and industrial 101 — — 394 495 Consumer — — — — — Total other loans 101 — — 394 495 Total acquired loans $ 2,771 $ 44 $ — $ 7,832 $ 10,647 Loans exhibiting potential credit weaknesses that deserve management’s close attention and that, if left uncorrected, may result in deterioration of the repayment capacity of the borrower, are categorized as special mention. Loans with well-defined credit weaknesses including payment defaults, declining collateral values, frequent overdrafts, operating losses, increasing balance sheet leverage, inadequate cash flow, project cost overruns, unreasonable construction delays, past due real estate taxes or exhausted interest reserves are assigned an internal risk rating of substandard. A loan with a weakness so severe that collection in full is highly questionable or improbable will be assigned an internal risk rating of doubtful. The following tables summarize the Company’s commercial Non-ASC 310-30 and New loans by key indicators of credit quality. Loans accounted for under ASC 310-30 are excluded from the following analysis because their related allowance is determined by loan pool performance: September 30, 2018 Pass Special Mention Substandard Doubtful (Dollars in thousands) New loans: Commercial real estate $ 2,515,933 $ 9,325 $ 3,490 $ — Owner-occupied commercial real estate 1,131,769 584 2,440 — Construction, land and development 754,972 — — — Commercial and industrial 1,868,553 21,991 11,501 — Total new loans $ 6,271,227 $ 31,900 $ 17,431 $ — Acquired loans: Commercial real estate $ 100,413 $ — $ 3,951 $ — Owner-occupied commercial real estate 80,835 — 573 — Construction, land and development 36,881 — — — Commercial and industrial 42,447 1,024 3,172 — Total acquired loans $ 260,576 $ 1,024 $ 7,696 $ — December 31, 2017 Pass Special Substandard Doubtful (Dollars in thousands) New loans: Commercial real estate $ 2,095,560 $ 6,066 $ 2,162 $ — Owner-occupied commercial real estate 987,781 — — — Construction, land and development 684,462 — — — Commercial and industrial 1,617,462 16,910 — — Total new loans $ 5,385,265 $ 22,976 $ 2,162 $ — Acquired loans: Commercial real estate $ 33,496 $ — $ 4,240 $ — Owner-occupied commercial real estate 15,607 — 493 — Construction, land and development 5,889 — — — Commercial and industrial 4,324 — 738 — Total acquired loans $ 59,316 $ — $ 5,471 $ — Internal risk ratings are a key factor in identifying loans to be individually evaluated for impairment and impact management’s estimates of loss factors used in determining the amount of the ALL. The following tables show the Company’s investment in loans disaggregated based on the method of evaluating impairment: Loans - Recorded Investment Allowance for Credit Loss September 30, 2018 Individually Evaluated for Impairment Collectively Evaluated for Impairment ASC 310- 30 Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment ASC 310- 30 Loans (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ 2,528,748 $ — $ — $ 14,410 $ — Owner-occupied commercial real estate 2,899 1,131,894 — — 3,760 — 1-4 single family residential 1,637 2,243,502 — — 6,806 — Construction, land and development — 754,972 — — 5,121 — Home equity loans and lines of credit 126 59,603 — 63 415 — Total real estate loans $ 4,662 $ 6,718,719 $ — $ 63 $ 30,512 $ — Other loans: Commercial and industrial $ 16,708 $ 1,885,337 $ — $ 1,593 $ 17,878 $ — Consumer — 3,976 — — 69 — Total other loans $ 16,708 $ 1,889,313 $ — $ 1,593 $ 17,947 $ — Acquired loans: Real estate loans: Commercial real estate $ 3,396 $ 100,968 $ 133,778 $ — $ 188 $ 1,556 Owner-occupied commercial real estate — 81,408 — — 51 — 1-4 single family residential 267 148,392 32,240 — 144 8 Construction, land and development — 36,881 28,590 — 130 103 Home equity loans and lines of credit 494 39,637 — — 204 — Total real estate loans $ 4,157 $ 407,286 $ 194,608 $ — $ 717 $ 1,667 Other loans: Commercial and industrial $ 3,442 $ 43,201 $ 19,503 $ 394 $ 53 $ 80 Consumer — 13,950 1,259 — 3 119 Total other loans $ 3,442 $ 57,151 $ 20,762 $ 394 $ 56 $ 199 Total Loans: Unallocated $ — $ 9,316,808 $ — $ — $ — $ — Loans - Recorded Investment Allowance for Credit Loss December 31, 2017 Individually Evaluated for Impairment Collectively Evaluated for Impairment ASC 310- 30 Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment ASC 310- 30 Loans (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ 2,103,788 $ — $ — $ 12,084 $ — Owner-occupied commercial real estate — 987,781 — — 3,310 — 1-4 single family residential 1,096 2,184,266 — — 7,769 — Construction, land and development — 684,462 — — 4,164 — Home equity loans and lines of credit 130 59,506 — 66 409 — Total real estate loans $ 1,226 $ 6,019,803 $ — $ 66 $ 27,736 $ — Other loans: Commercial and industrial $ — $ 1,634,372 $ — $ — $ 14,702 $ — Consumer — 5,984 — — 121 — Total other loans $ — $ 1,640,356 $ — $ — $ 14,823 $ — Acquired Loans: Real estate loans: Commercial real estate $ 3,893 $ 33,843 $ 104,335 $ 129 $ 209 $ 1,448 Owner-occupied commercial real estate — 16,100 — — 55 — 1-4 single family residential 267 57,428 27,513 — 184 25 Construction, land and development — 5,889 13,167 — 36 145 Home equity loans and lines of credit 495 34,094 — — 199 — Total real estate loans $ 4,655 $ 147,354 $ 145,015 $ 129 $ 683 $ 1,618 Other loans: Commercial and industrial $ 272 $ 4,790 $ 12,631 $ 272 $ 41 $ 126 Consumer — 259 1,423 — 6 145 Total other loans $ 272 $ 5,049 $ 14,054 $ 272 $ 47 $ 271 Total Loans: Unallocated $ — $ 7,977,784 $ — $ — $ 1,500 $ — The following tables set forth certain information regarding the Company’s impaired loans (excluding loans accounted for under ASC 310-30) that were evaluated for specific reserves: Impaired Loans - With Allowance Impaired Loans - With no Allowance September 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ — $ — $ 459 $ 470 Owner-occupied commercial real estate — — — 2,440 2,440 1-4 single family residential — — — 1,637 1,641 Construction, land and development — — — — — Home equity loans and lines of credit 63 66 63 63 63 Total real estate loans $ 63 $ 66 $ 63 $ 4,599 $ 4,614 Other loans: Commercial and industrial $ 16,708 $ 16,708 $ 1,593 $ — $ — Consumer — — — — — Total other loans $ 16,708 $ 16,708 $ 1,593 $ — $ — Acquired loans: Real estate loans: Commercial real estate $ — $ — $ — $ 3,396 $ 4,991 Owner-occupied commercial real estate — — — — — 1-4 single family residential — — — 267 267 Construction, land and development — — — — — Home equity loans and lines of credit — — — 495 495 Total real estate loans $ — $ — $ — $ 4,158 $ 5,753 Other loans: Commercial and industrial $ 394 $ 394 $ 394 $ 3,047 $ 6,948 Consumer — — — — — Total other loans $ 394 $ 394 $ 394 $ 3,047 $ 6,948 Impaired Loans - With Allowance Impaired Loans - With no Allowance December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ — $ — $ — $ — Owner-occupied commercial real estate — — — — — 1-4 single family residential — — — 1,096 1,096 Construction, land and development — — — — — Home equity loans and lines of credit 66 66 66 63 63 Total real estate loans $ 66 $ 66 $ 66 $ 1,159 $ 1,159 Other loans: Commercial and industrial $ — $ — $ — $ — $ — Consumer — — — — — Total other loans $ — $ — $ — $ — $ — Acquired loans: Real estate loans: Commercial real estate $ 336 $ 347 $ 129 $ 3,557 $ 4,991 Owner-occupied commercial real estate — — — — — 1-4 single family residential — — — 267 267 Construction, land and development — — — — — Home equity loans and lines of credit — — — 495 495 Total real estate loans $ 336 $ 347 $ 129 $ 4,319 $ 5,753 Other loans: Commercial and industrial $ 272 $ 272 $ 272 $ — $ — Consumer — — — — — Total other loans $ 272 $ 272 $ 272 $ — $ — The following tables present the average recorded investment and interest income recognized during the period subsequent to impairment on loans individually evaluated for impairment: Three Months Ended September 30, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with no related allowance: Real estate loans: Commercial real estate $ 3,887 $ — $ 3,629 $ — Owner-occupied commercial real estate 2,440 — — — 1-4 single family residential 1,903 — 1,363 — Construction, land and development — — — — Home equity loans and lines of credit 558 — 534 — Total real estate loans $ 8,788 $ — $ 5,526 $ — Other loans: Commercial and industrial $ 3,038 $ — $ — $ — Consumer — — — — Total other loans $ 3,038 $ — $ — $ — Impaired loans with an allowance: Real estate loans: Commercial real estate $ — $ — $ 336 $ — Owner-occupied commercial real estate — — — — 1-4 single family residential — — 497 — Construction, land and development — — — — Home equity loans and lines of credit 63 — 66 — Total real estate loans $ 63 $ — $ 899 $ — Other loans: Commercial and industrial $ 17,102 $ — $ 299 $ — Consumer — — — — Total other loans $ 17,102 $ — $ 299 $ — Nine Months Ended September 30, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with no related allowance: Real estate loans: Commercial real estate $ 3,636 $ — $ 3,677 $ — Owner-occupied commercial real estate 1,058 — — — 1-4 single family residential 1,537 — 1,174 — Construction, land and development — — — — Home equity loans and lines of credit 558 — 750 — Total real estate loans $ 6,789 $ — $ 5,601 $ — Other loans: Commercial and industrial $ 1,284 $ — $ — $ — Consumer — — — — Total other loans $ 1,284 $ — $ — $ — Impaired loans with an allowance: Real estate loans: Commercial real estate $ — $ — $ 529 $ — Owner-occupied commercial real estate — — — — 1-4 single family residential — — 509 — Construction, land and development — — — — Home equity loans and lines of credit 65 — 201 — Total real estate loans $ 65 $ — $ 1,239 $ — Other loans: Commercial and industrial $ 11,528 $ — $ 333 $ — Consumer — — — — Total other loans $ 11,528 $ — $ 333 $ —

Goodwill and Intangibles

Goodwill and Intangibles	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	GOODWILL AND INTANGIBLES Goodwill and other intangible assets are summarized as follows: September 30, 2018 December 31, 2017 (Dollars in thousands) Goodwill $ 139,529 $ 81,204 Core deposit intangible 18,950 14,370 Less: Accumulated amortization (11,737 ) (10,702 ) Net core deposit intangible $ 7,213 $ 3,668 Amortization expense for core deposit intangibles for the nine months ended September 30, 2018 and 2017 totaled $1.0 million and $768 thousand , respectively. The estimated amount of amortization expense for core deposit intangible assets to be recognized for the remainder of 2018 through 2022 is as follows: Remainder of 2018 2019 2020 2021 2022 (Dollars in thousands) Core deposit intangible $ 370 $ 1,481 $ 968 $ 818 $ 818

Derivatives

Derivatives	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	DERIVATIVES The Company uses interest rate swaps to manage interest rate risk related to borrowings that expose the Company to variability in cash flows due to changes in interest rates. The Company entered into LIBOR-based forward interest rate swaps that are designated as cash flow hedges with the objective of limiting the variability of forecasted interest payment cash flows resulting from changes in the benchmark interest rate LIBOR. Changes in the fair value of interest rate swaps designated as cash flow hedging instruments are reported in accumulated other comprehensive income ("AOCI") and subsequently reclassified into interest expense in the same period in which the related interest on the floating-rate borrowings affects earnings. The Company is also a party to interest rate derivatives that are not designated as hedging instruments. The Company uses interest rate derivative contracts, such as swaps and caps, in the normal course of business to meet the financial needs of its customers. The interest rate swaps that the Company enters into with customers allow the customers to convert variable rate loans to fixed rates. At the same time the interest rate swap is entered into with the customer, an offsetting interest rate swap is entered into with another financial institution. The changes in the fair value of the swaps offset each other, except for any differences in the credit risk of the counterparties, which is determined by considering the risk rating, probability of default and loss given default of each counterparty. The Company recorded $4.4 million and $1.5 million of derivative contract fees in noninterest income in the accompanying Consolidated Statement of Income for the three months ended September 30, 2018 and 2017 , respectively, and $10.8 million and $4.8 million for the nine months ended September 30, 2018 and 2017 , respectively. In addition, the Company has entered into three risk participation agreements. The notional amount of the risk participation agreements sold was $34.3 million as of September 30, 2018 . Assuming all underlying third party customers referenced in the swap agreements defaulted at September 30, 2018 , there would be an immaterial amount of exposure to the company. These risk participation agreements mature in 2021 . No credit changes in counterparty credit were identified. There was no change in the fair value of derivative assets and derivative liabilities attributable to credit risk included in noninterest expense in the Consolidated Statements of Income for the three or nine months ended September 30, 2018 or 2017 . The following tables summarize the Company’s derivatives outstanding included in other assets and other liabilities in the accompanying Consolidated Balance Sheets: September 30, 2018 Derivative Assets Derivative Liabilities Notional Fair Value Notional Fair Value (Dollars in thousands) Derivatives designated as cash flow hedges: Interest rate contracts - pay fixed, receive floating $ 250,000 $ 1,750 $ — $ — Total cash flow hedges 250,000 1,750 — — Derivatives not designated as hedges: Interest rate contracts - pay floating, receive fixed 543,748 6,682 1,005,701 25,549 Interest rate contracts - pay fixed, receive floating 1,005,701 22,954 543,748 4,087 Interest rate caps purchased 94,534 312 — — Interest rate caps sold — — 94,534 312 Risk participation agreements — — 34,307 — Total derivatives not designated as hedges 1,643,983 29,948 1,678,290 29,948 Total derivatives $ 1,893,983 $ 31,698 $ 1,678,290 $ 29,948 December 31, 2017 Derivative Assets Derivative Liabilities Notional Fair Value Notional Fair Value (Dollars in thousands) Derivatives not designated as hedges: Interest rate contracts - pay floating, receive fixed $ 757,887 $ 11,678 $ 380,233 $ 4,180 Interest rate contracts - pay fixed, receive floating 380,233 — 757,887 7,498 Interest rate caps - purchased 94,884 155 — — Interest rate caps - sold — — 94,884 155 Total derivatives $ 1,233,004 $ 11,833 $ 1,233,004 $ 11,833 The following table presents the net gains (losses) recorded in accumulated other comprehensive income and the Consolidated Statements of Income relating to the cash flow derivative instruments for the nine months ended September 30, 2018 : September 30, 2018 Amount of Gain (Loss) Recognized in AOCI Amount of Gain (Loss) Reclassified from AOCI to Interest Expense Location of Gain (Loss) Reclassified from AOCI into Income (Dollars in thousands) Derivatives designated as cash flow hedges: Interest rate contracts - pay fixed, receive floating 1,313 — Interest on borrowings During the three or nine months ended September 30, 2018 , no derivative positions designated as cash flow hedges were discontinued and none of the gains or losses reported in AOCI were reclassified into earnings as a result of the discontinuance of cash flow hedges or because of the early extinguishment of borrowings. The derivative transactions entered into with a financial institution are subject to an enforceable master netting arrangement. The following tables summarize the gross and net fair values of the Company’s derivatives outstanding with this counterparty included in other liabilities in the accompanying Consolidated Balance Sheets: September 30, 2018 Gross amounts of recognized liabilities Gross amounts offset in the consolidated balance sheets Net amounts in the consolidated balance sheets (Dollars in thousands) Offsetting derivative liabilities: Counterparty A - Interest rate contracts $ 24,648 $ (1,694 ) $ 22,954 Centrally Cleared - Interest rate contracts $ 901 $ (4,989 ) $ (4,088 ) December 31, 2017 Gross amounts of recognized liabilities Gross amounts offset in the consolidated balance sheets Net amounts in the consolidated balance sheets (Dollars in thousands) Offsetting derivative liabilities: Counterparty A - Interest rate contracts $ 11,833 $ (4,491 ) $ 7,342 At September 30, 2018 , the Company has pledged investment securities available for sale with a carrying amount of $2.5 million as collateral for the interest rate swaps in a liability position. The amount of collateral required to be posted by the Company varies based on the settlement value of outstanding swaps. As of September 30, 2018 and December 31, 2017 , substantially all of the floating rate terms within the interest rate contracts held by the Company were indexed to 1-month LIBOR . The fair value of the derivative assets and liabilities are included in a table in Note 14 “Fair Value Measurements,” in the line items “Derivative assets” and “Derivative liabilities.”

Deposits

Deposits	9 Months Ended
	Sep. 30, 2018
Banking and Thrift [Abstract]
Deposits	DEPOSITS The following table sets forth the Company’s deposits by category: September 30, 2018 December 31, 2017 (Dollars in thousands) Noninterest-bearing demand deposits $ 1,577,741 $ 1,236,685 Interest-bearing demand deposits 1,207,859 1,454,097 Interest-bearing NOW accounts 410,226 363,191 Savings and money market accounts 2,607,093 3,013,237 Time deposits 4,353,196 2,606,717 Total deposits $ 10,156,115 $ 8,673,927 Time deposits $100,000 and greater $ 3,005,138 $ 1,983,445 Time deposits greater than $250,000 1,623,796 1,078,702 The aggregate amount of overdraft demand deposits reclassified to loans was $2.0 million at September 30, 2018 . The aggregate amount of maturities for time deposits for each of the five years following September 30, 2018 totaled $3.46 billion , $836.9 million , $20.4 million , $11.6 million and $21.6 million , respectively. The Company holds brokered deposits through an insured deposit sweep program of $419.8 million and $656.4 million at September 30, 2018 and December 31, 2017 , respectively. The Company holds brokered certificates of deposit of $501.2 million and $85.2 million at September 30, 2018 and December 31, 2017 , respectively.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Accumulated Other Comprehensive Income	ACCUMULATED OTHER COMPREHENSIVE INCOME Changes in AOCI for the periods indicated are summarized as follows: Three Months Ended September 30, 2018 2017 Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax (Dollars in thousands) Unrealized gains (losses) on debt securities available for sale: Balance at beginning of period $ (25,353 ) $ 6,326 $ (19,027 ) $ 25,468 $ (9,744 ) $ 15,724 Net unrealized holding gain (loss) arising during the period (11,095 ) 2,768 (8,327 ) (967 ) 369 (598 ) Amounts reclassified to (gain) loss on investment securities, net 1,677 (418 ) 1,259 (1,409 ) 540 (869 ) Balance at end of period (34,771 ) 8,676 (26,095 ) 23,092 (8,835 ) 14,257 Unrealized gains (losses) on derivative instruments: Balance at beginning of period 124 (31 ) 93 — — — Net unrealized holding gains (losses) arising during the period 1,626 (406 ) 1,220 — — — Balance at end of period 1,750 (437 ) 1,313 — — — Total accumulated other comprehensive income (loss) $ (33,021 ) $ 8,239 $ (24,782 ) $ 23,092 $ (8,835 ) $ 14,257 Nine Months Ended September 30, 2018 2017 Before Tax Net Before Tax Net (Dollars in thousands) Balance at beginning of period $ 14,402 $ (5,509 ) $ 8,893 $ (6,504 ) $ 2,509 $ (3,995 ) Unrealized gain (loss) on investment securities available for sale: Net unrealized holdings gain (loss) arising during the period (48,163 ) 12,017 (36,146 ) 31,650 (12,131 ) 19,519 Amounts reclassified to (gain) loss on investment securities 577 (144 ) 433 (2,054 ) 787 (1,267 ) Cumulative adjustment from adoption of new accounting standards (1,587 ) 2,312 725 — — — Balance at end of period (34,771 ) 8,676 (26,095 ) 23,092 (8,835 ) 14,257 Unrealized gains (losses) on derivative instruments: Balance at beginning of period — — — — — — Net unrealized holding gains (losses) arising during the period 1,750 (437 ) 1,313 — — — Balance at end of period 1,750 (437 ) 1,313 — — — Total accumulated other comprehensive income (loss) $ (33,021 ) $ 8,239 $ (24,782 ) $ 23,092 $ (8,835 ) $ 14,257

Basic and Diluted Earnings Per

Basic and Diluted Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Basic and Diluted Earnings Per Share	BASIC AND DILUTED EARNINGS PER SHARE Basic earnings per share (“EPS”) is calculated by dividing net income available to common stockholders by the weighted average number of common shares outstanding during the period. Diluted EPS reflect the effect of common stock equivalents, including stock options and unvested shares, calculated using the treasury stock method. Common stock equivalents are excluded from the computation of diluted EPS in periods in which the effect is anti-dilutive. The following table presents the computation of basic and diluted EPS: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (Dollars in thousands, except share and per share data) Net income available to common stockholders $ 43,480 $ 32,160 $ 126,313 $ 106,230 Weighted average number of common shares - basic 46,693,707 43,333,947 46,213,176 42,580,426 Effect of dilutive securities: Employee stock-based compensation awards 2,111,164 2,855,521 2,259,481 3,380,169 Weighted average number of common shares - diluted 48,804,871 46,189,468 48,472,657 45,960,595 Basic earnings per share $ 0.93 $ 0.74 $ 2.73 $ 2.49 Diluted earnings per share $ 0.89 $ 0.70 $ 2.61 $ 2.31 Weighted average number of anti-dilutive equity awards 48,708 41,040 25,332 20,942

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The Company uses an estimated annual effective tax rate method in computing its interim tax provision. This effective tax rate is based on forecasted annual pre-tax income, permanent tax differences and statutory tax rates. The effective tax rates for the three months ended September 30, 2018 and 2017 were 23.5% and 30.2% , respectively. The decrease in the effective tax rate for the third quarter of 2018 was primarily due to the Tax Cuts and Jobs Act of 2017 (the "TCJA") which resulted in a reduction in the maximum federal corporate income tax rate from 35% to 21%, effective January 1, 2018. This was partially offset by a decrease in excess tax benefits recognized at settlement for share-based payments which resulted in recording a $168 thousand tax benefit in the Consolidated Statements of Income for the quarter ended September 30, 2018 compared to $2.1 million for the quarter ended September 30, 2017 . The tax rate differs from the statutory rate due to the impact of tax benefits related to bank-owned life insurance, dividends received deductions and certain stock-based compensation awards. The effective tax rates for the nine months ended September 30, 2018 and 2017 were 21.7% and 19.8% , respectively. The increase in the effective tax rate for the nine months ended September 30, 2018 was due to a decrease in excess tax benefits recognized at settlement for share-based payments which resulted in recording a $2.9 million tax benefit in the Consolidated Statements of Income for the nine months ended September 30, 2018 compared to $18.0 million for the nine months ended September 30, 2017 . This was partially offset by the TCJA which resulted in a reduction in the maximum federal corporate income tax rate effective January 1, 2018, as well as higher levels of pre-tax income.

Stock-Based Compensation and Ot

Stock-Based Compensation and Other Benefit Plans	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation and Other Benefit Plans	STOCK-BASED COMPENSATION AND OTHER BENEFIT PLANS 2009 Stock Option Plan Option grant activity for the period indicated is summarized as follows: 2009 Stock Option Plan Options Weighted Average Exercise Price Outstanding at January 1, 2018 1,314,924 $ 20.65 Granted — — Exercised (142,602 ) 21.15 Forfeited — — Expired — — Outstanding at September 30, 2018 1,172,322 $ 20.58 Exercisable at September 30, 2018 1,172,322 $ 20.58 Vested at September 30, 2018 1,172,322 $ 20.58 Vested and expected to vest at September 30, 2018 1,172,322 $ 20.58 There is no unrecognized compensation cost related to the 2009 Stock Option Plan for share awards outstanding at September 30, 2018 . 2013 Stock Incentive Plan Option grant activity for the period indicated is summarized as follows: 2013 Stock Incentive Plan Options Options Weighted Average Exercise Price Outstanding at January 1, 2018 1,424,953 $ 20.79 Granted — — Exercised (245,611 ) 20.53 Forfeited — — Expired — — Outstanding at September 30, 2018 1,179,342 $ 20.84 Exercisable at September 30, 2018 1,179,342 $ 20.84 Vested at September 30, 2018 1,179,342 $ 20.84 Vested and expected to vest at September 30, 2018 1,179,342 $ 20.84 There is no unrecognized compensation cost related to the 2013 Stock Incentive Plan for share awards outstanding at September 30, 2018 . 2016 Stock Incentive Plan Option grant activity for the period indicated is summarized as follows: 2016 Stock Incentive Plan Options Options Weighted Average Exercise Price Outstanding at January 1, 2018 762,500 $ 36.64 Granted — — Exercised — — Forfeited (30,000 ) 36.11 Expired — — Outstanding at September 30, 2018 732,500 $ 36.66 Exercisable at September 30, 2018 — $ — Vested at September 30, 2018 — $ — Vested and expected to vest at September 30, 2018 732,500 $ 36.66 The total unrecognized compensation cost of $3.7 million related to the 2016 Stock Incentive Plan for share awards outstanding at September 30, 2018 will be recognized over a weighted average remaining period of 2.92 years . 2016 Incentive Plan - Restricted Stock Unit Awards On February 21, 2018, the Compensation Committee granted certain non-employee Directors of the Company a portion of their Directors' compensation for fiscal year 2018 in the form of restricted stock units (the "Directors' RSUs"). Each RSU constitutes the right to receive from the Company on the date the RSU is settled, one share of Class A Common Stock of the Company. A total of 19,015 Directors' RSUs were granted with a grant date fair value of $1.1 million . Twenty-five percent ( 25% ) of the RSUs vested on both March 31, 2018, June 30, 2018, and September 30, 2018 , and an additional twenty-five percent ( 25% ) will vest on December 31, 2018 provided the participant remains in a continuous service relationship with the Company through such applicable date. Compensation expense will be recognized on a straight-line basis over the requisite vesting period ending December 31, 2018 . On March 21, 2018, the Compensation Committee granted a target of 84,836 and a maximum of 106,043 restricted stock units (the "Executive RSUs") of Class A Common Stock to certain Executives. The total target grant date fair value of the RSU Award was $4.8 million , up to a maximum of $5.9 million , and will be recognized on a straight-line basis as compensation expense over the requisite vesting period ending December 31, 2020. On five different dates during the period ended September 30, 2018 , the Company granted a total of 53,552 restricted shares to employees (the "Employee RSUs") that vest in-full (i.e. cliff vesting) on the 5 -year anniversary of the grant date. The fair value of the Awards on the grant date was $3.0 million and will be recognized as compensation expense over the requisite vesting period ending on the respective 5 -year anniversary of the Employee RSU Award's grant date. The following table presents the activity during the nine months ended September 30, 2018 related to restricted stock units from the 2016 Plan: 2016 Stock Incentive Plan Restricted Stock Awards Restricted Stock Unit Awards Performance Restricted Stock Unit Awards Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value (Dollars in thousands, except per share data) Outstanding at January 1, 2018 96,133 $ 42.23 88,015 $ 50.34 73,144 $ 47.85 Granted — — 72,567 56.52 84,836 56.10 Vested — — (20,459 ) 52.38 — — Forfeited — — (5,300 ) 52.62 — — Outstanding at September 30, 2018 96,133 $ 42.23 134,823 $ 53.27 157,980 $ 52.28 The actual number of Performance Restricted Stock Units issued at the vesting date could range from 0% to 125% of the initial grant, depending on actual performance achieved. A summary of selected data related to stock-based compensation expense for the nine months ended September 30, 2018 and 2017 are as follows: Restricted Stock Awards Restricted Stock Unit Awards Performance Restricted Stock Unit Awards Nine Months Ended September 30, 2018 2017 2018 2017 2018 2017 (Dollars in thousands) Stock-based compensation expense $ 1,968 $ 2,570 $ 1,710 $ 863 $ 1,855 $ 649 Unrecognized compensation expense related to stock-based compensation $ 1,145 $ 4,216 $ 6,183 $ 1,067 $ 5,437 $ 2,851 Weighted-average life over which expense is expected to be recognized (years) 0.78 1.41 4.05 3.65 1.96 2.25 Executive Incentive Plan During the year ended December 31, 2015, the Compensation Committee of the Board of Directors of the Company approved the adoption of the FCB Financial Holdings, Inc. Executive Incentive Plan (the “EIP”). The EIP provides for Annual Incentive Awards and Long-Term Incentive Awards, both of which are subject to achievement of specified performance goals. Long-Term Incentive Awards On March 21, 2018, the Compensation Committee granted a Long-Term Award of cash phantom units (“CPUs”) under the Long-Term Incentive component of the EIP which covers a three -year period ending December 31, 2020 (the “Performance Period”). Granted under the award is a target of 18,050 CPUs and a maximum of 22,562 CPUs to a certain Executive. Each CPU is the equivalent in value of a share of Class A Common Stock of the Company, par value $0.001 per share. The total target grant date fair value of the CPU Award was $1.0 million , up to a maximum of $1.3 million , and will be recognized on a straight-line basis as compensation expense over the requisite period ending December 31, 2020. The Company recognized $91 thousand and $193 thousand of compensation expense during the three and nine months ended September 30, 2018 , respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES The Company issues off balance sheet financial instruments in connection with its lending activities and to meet the financing needs of its customers. These financial instruments include commitments to fund loans and lines of credit as well as commercial and standby letters of credit. These commitments expose the Company to varying degrees of credit and market risk which are essentially the same as those involved in extending loans to customers. The Company follows the same credit policies in making commitments as it does for instruments recorded on the Company’s consolidated balance sheet. Collateral is obtained based on management’s assessment of the customer’s credit risk. The Company’s exposure to credit loss is represented by the contractual amount of these commitments. The Company’s reserve for unfunded commitments totaled $1.5 million as of September 30, 2018 and $1.1 million as of December 31, 2017 . Fees collected on off balance sheet financial instruments represent the fair value of those commitments and are deferred and amortized over their term. Financial Instruments Commitments Unfunded commitments are as follows: September 30, 2018 December 31, 2017 (Dollars in thousands) Commitments to fund loans $ 1,159,541 $ 926,405 Unused lines of credit 774,695 571,587 Commercial and standby letters of credit 50,945 46,520 Total $ 1,985,181 $ 1,544,512 Commitments to fund loans: Commitments to fund loans are agreements to lend funds to customers as long as there is no violation of any condition established in the contract. To accommodate the financial needs of customers, the Company makes commitments under various terms to lend funds to consumers and businesses. Commitments to fund loans generally have fixed expiration dates or other termination clauses and may require payment of a fee. Many of these commitments are expected to expire without being funded and, therefore, the total commitment amounts do not necessarily represent future liquidity requirements. The Company evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral required in connection with a commitment to fund is based on management’s credit evaluation of the counterparty. Unused lines of credit: Unfunded commitments under lines of credit include commercial, commercial real estate, home equity and consumer lines of credit to existing customers. Some of these commitments may mature without being fully funded. Commercial and standby letters of credit: Letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. Letters of credit are primarily issued to support trade transactions or guarantee arrangements. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. The Company generally holds collateral supporting those commitments if deemed necessary. Other Commitments and Contingencies Legal Proceedings The Company, from time to time, is involved as plaintiff or defendant in various legal actions arising in the normal course of business. While the ultimate outcome of any such proceedings cannot be predicted with certainty, it is the opinion of management, based upon advice of legal counsel, that no proceedings exist, either individually or in the aggregate, which, if determined adversely to the Company, would have a material effect on the Company’s consolidated balance sheet, results of operations or cash flows.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS When determining the fair value measurements for assets and liabilities and the related fair value hierarchy, the Company considers the principal or most advantageous market in which it would transact and the assumptions that market participants would use when pricing the asset or liability. When possible, the Company looks to active and observable markets to price identical assets or liabilities. When identical assets and liabilities are not traded in active markets, the Company looks to market observable data for similar assets and liabilities. It is the Company’s policy to maximize the use of observable inputs, minimize the use of unobservable inputs and use unobservable inputs to measure fair value to the extent that observable inputs are not available. The need to use unobservable inputs generally results from the lack of market liquidity, resulting in diminished observability of both actual trades and assumptions that would otherwise be available to value instruments, or the value of underlying collateral is not market observable. Although third party price indications may be available for an asset or liability, limited trading activity would make it difficult to support the observability of these quotations. Financial Instruments Carried at Fair Value on a Recurring Basis The following is a description of the valuation methodologies used for financial instruments measured at fair value on a recurring basis, as well as the general classification of each instrument under the valuation hierarchy. Investment Securities—Investment securities available for sale are carried at fair value on a recurring basis. When available, fair value is based on quoted prices for the identical security in an active market and as such, would be classified as Level 1. If quoted market prices are not available, fair values are estimated using quoted prices of securities with similar characteristics, discounted cash flows or matrix pricing models. Investment securities available for sale for which Level 1 valuations are not available are classified as Level 2 if the valuation incorporates primarily observable inputs. Level 2 securities include U.S. Government agencies and sponsored enterprises obligations and agency mortgage-backed securities; state and municipal obligations; asset-backed securities; and corporate debt and other securities. Pricing of these securities is generally spread driven. Observable inputs that may impact the valuation of these securities include benchmark yield curves, credit spreads, reported trades, dealer quotes, bids, issuer spreads, current rating, historical constant prepayment rates, historical voluntary prepayment rates, structural and waterfall features of individual securities, published collateral data, and for certain securities, historical constant default rates and default severities. Derivatives—Derivatives are reported at estimated fair value utilizing Level 2 inputs and are included in other assets and other liabilities and consist of interest rate swaps, interest rate caps, and risk participation agreements where there is no significant deterioration in the counterparties (loan customers) credit risk since origination of the interest rate swap, interest rate cap, or risk participation agreements. The Company values its interest rate swap, interest rate cap, and risk participation agreement positions using market prices provided by a third party which uses primarily observable market inputs. Derivatives are further described in Note 7 “Derivatives.” For purposes of potential valuation adjustments to our derivative positions, the Company evaluates the credit risk of its counterparties as well as its own credit risk. Accordingly, the Company has considered factors such as the likelihood of default, expected loss given default, net exposures and remaining contractual life, among other things, in determining if any estimated fair value adjustments related to credit risk are required. The Company reviews counterparty exposure quarterly, and when necessary, appropriate adjustments are made to reflect the exposure. For the three or nine months ended September 30, 2018 and 2017 , the Company has not realized any losses due to a counterparty’s inability to pay any net uncollateralized position. As of September 30, 2018 , there were no interest rate derivatives classified as Level 3. The following tables present the assets and liabilities measured at fair value on a recurring basis: September 30, 2018 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: U.S. Government agencies and sponsored enterprises obligations $ — $ 84,232 $ — $ 84,232 U.S. Government agencies and sponsored enterprises mortgage-backed securities — 604,158 — 604,158 State and municipal obligations — 22,882 — 22,882 Asset-backed securities — 778,322 — 778,322 Corporate bonds and other debt securities 52,966 733,143 — 786,109 Preferred stocks and other equity securities 12,590 58,425 — 71,015 Derivative assets — 31,699 — 31,699 Total $ 65,556 $ 2,312,861 $ — $ 2,378,417 Liabilities: Derivative liabilities $ — $ 29,949 $ — $ 29,949 Total $ — $ 29,949 $ — $ 29,949 December 31, 2017 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: U.S. Government agencies and sponsored enterprises obligations $ — $ 42,838 $ — $ 42,838 U.S. Government agencies and sponsored enterprises mortgage-backed securities — 595,237 — 595,237 State and municipal obligations — 26,172 — 26,172 Asset-backed securities — 610,546 — 610,546 Corporate bonds and other debt securities 55,970 699,933 — 755,903 Preferred stocks and other equity securities 12,954 77,153 — 90,107 Derivative assets — 11,833 — 11,833 Total $ 68,924 $ 2,063,712 $ — $ 2,132,636 Liabilities: Derivative liabilities $ — $ 11,833 $ — $ 11,833 Total $ — $ 11,833 $ — $ 11,833 The Company's policy is to recognize transfers into or out of a level of the fair value hierarchy as of the end of the reporting period. There were no transfers of financial assets between levels of the fair value hierarchy during the three or nine months ended September 30, 2018 . The inputs used to determine the estimated fair value of loans include market conditions, loan term, underlying collateral characteristics and discount rates. The inputs used to determine fair value of OREO include market conditions, estimated marketing period or holding period, underlying collateral characteristics and discount rates. For the three or nine months ended September 30, 2018 , there was not a change in the methods or significant assumptions used to estimate fair value. Financial Instruments Measured at Fair Value on a Non-Recurring Basis The following is a description of the methodologies used to estimate the fair values of assets and liabilities measured at fair value on a non-recurring basis, and the level within the fair value hierarchy in which those measurements are typically classified. Impaired loans and OREO—The carrying amount of collateral dependent impaired loans is typically based on the fair value of the underlying collateral, which may be real estate or other business assets, less estimated costs to sell. The carrying value of OREO is initially measured based on the fair value, less estimated cost to sell, of the real estate acquired in foreclosure and subsequently adjusted to the lower of cost or estimated fair value, less estimated cost to sell. Fair values of real estate collateral are typically based on real estate appraisals which utilize market and income valuation techniques incorporating both observable and unobservable inputs. When current appraisals are not available, the Company may use brokers’ price opinions, home price indices, or other available information about changes in real estate market conditions to adjust the latest appraised value available. These adjustments to appraised values may be subjective and involve significant management judgment. The fair value of collateral consisting of other business assets is generally based on appraisals that use market approaches to valuation, incorporating primarily unobservable inputs. Fair value measurements related to collateral dependent impaired loans and OREO are classified within level 3 of the fair value hierarchy. The following table shows significant unobservable inputs used in the non-recurring fair value measurement of level 3 assets and liabilities: Level 3 Assets: September 30, 2018 December 31, 2017 Valuation Technique Unobservable Inputs Range (Weighted Average) (Dollars in thousands) Impaired loans $ 28,969 $ 6,153 Third party appraisals and discounted cash flows Collateral discounts and discount rates 0% - 100% (7.1%) Other real estate owned 10,534 14,906 Third party appraisals Collateral discounts and estimated cost to sell 10 % The following table provides information about certain assets measured at fair value on a non-recurring basis: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (Dollars in thousands) Negative valuation adjustments: Impaired loans $ 122 $ — $ 1,715 $ — Foreclosed real estate 9 54 1,106 437 Impairment charges resulting from the non-recurring changes in fair value of the underlying collateral of impaired loans are included in the provision for loan losses in the Consolidated Statements of Income. Impairment charges resulting from the non-recurring changes in fair value of OREO are included in loan and other real estate related expenses in the Consolidated Statements of Income. The carrying amounts and estimated fair values, as well as the level within the fair value hierarchy, of the Company’s financial instruments are as follows: September 30, 2018 Carrying Value Fair Value Level 1 Level 2 Level 3 (Dollars in thousands) Financial Assets: Cash and cash equivalents $ 200,509 $ 200,509 $ 200,509 $ — $ — Available for sale debt securities 2,275,703 2,275,703 52,966 2,222,737 — Preferred stocks and other equity securities 71,015 71,015 12,590 58,425 — FHLB and other bank stock 65,847 65,847 — 65,847 — Loans, net 9,263,660 9,185,518 — — 9,185,518 Loans held for sale 980 980 — 980 — Bank-owned life insurance 215,421 215,421 — 215,421 — Derivative assets 31,699 31,699 — 31,699 — Financial Liabilities: Deposits $ 10,156,115 $ 10,133,649 $ — $ 10,133,649 $ — Advances from the FHLB and other borrowings 825,558 853,004 — 853,004 — Derivative liabilities 29,949 29,949 — 29,949 — December 31, 2017 Carrying Value Fair Value Level 1 Level 2 Level 3 (Dollars in thousands) Financial Assets: Cash and cash equivalents $ 115,921 $ 115,921 $ 115,921 $ — $ — Available for sale debt securities 2,030,696 2,130,696 55,970 1,974,726 — Preferred stocks and other equity securities 90,107 90,107 12,954 77,153 — FHLB and other bank stock 56,881 56,881 — 56,881 — Loans, net 7,930,639 7,877,094 — — 7,877,094 Loans held for sale 12,736 12,736 — 12,736 — Bank-owned life insurance 201,069 201,069 — 201,069 — Derivative assets 11,833 11,833 — 11,833 — Financial Liabilities: Deposits $ 8,673,927 $ 8,664,125 $ — $ 8,664,125 $ — Advances from the FHLB and other borrowings 749,113 740,941 — 740,941 — Derivative liabilities 11,833 11,833 — 11,833 — Certain financial instruments are carried at amounts that approximate fair value due to their short-term nature and generally negligible credit risk. Financial instruments for which fair value approximates the carrying amount at September 30, 2018 and December 31, 2017 , include cash and cash equivalents. The following methods and assumptions were used to estimate the fair value of each class of financial instruments. Estimates may differ from actual exit value as defined by ASC 820. FHLB and Other Bank Stock: FHLB and other bank stock can be liquidated only by redemption by the issuer, as there is no market for these securities. These securities are carried at par, which has historically represented the redemption price and is therefore considered to approximate fair value. Loans: Fair values for loans are based on a discounted cash flow methodology that considers various factors, including the type of loan and related collateral, classification status, fixed or variable interest rate, term of loan, whether or not the loan was amortizing and current discount rates. Loans are grouped together according to similar characteristics and are treated in the aggregate when applying various valuation techniques. The discount rates used for loans are based on current market rates for new originations of comparable credit risk and include adjustments for liquidity concerns. The ALL is considered a reasonable estimate of the required adjustment to fair value to reflect the impact of credit risk. Loans Held for Sale: Fair values of mortgage loans held for sale are based on commitments on hand from investors or prevailing market prices. Bank-owned Life Insurance: The Company holds life insurance policies on certain officers. The carrying value of these policies approximates fair value as it is based on the cash surrender value adjusted for other charges or amounts due that are probable at settlement. Deposits: The fair value of demand deposits, savings accounts and money market deposits is the amount payable on demand at the reporting date. The fair value of fixed-maturity certificates of deposit is estimated using discounted cash flow analysis and using the rates currently offered for deposits of similar remaining maturities. Advances from the FHLB and Other Borrowings: The fair value of advances from the FHLB and other borrowings are estimated by discounting the future cash flows using the current rate at which similar borrowings with similar remaining maturities could be obtained.

Revenue Recognition Revenue Rec

Revenue Recognition Revenue Recognition	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue Recognition	REVENUE RECOGNITION On January 1, 2018, the Company adopted ASU No. 2014-09 “Revenue from Contracts with Customers (Topic 606)" and all subsequent ASUs that modified Topic 606. As stated in Note 1. "Summary of Significant Accounting Policies", the implementation of the new standard did not have a material impact on the measurement or recognition of revenue; as such, a cumulative effect adjustment to opening retained earnings was not deemed necessary. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts were not adjusted and continue to be reported in accordance with the Company's historic accounting under Topic 605. Topic 606 does not apply to revenue associated with financial instruments, including revenue from loans and securities. In addition, certain noninterest income streams such as fees associated with financial guarantees, derivatives, transfers and servicing of loans and lease contracts are also not in scope of the new guidance. Topic 606 is applicable to noninterest revenue streams such as service charges and deposit related fees, interchange fees, merchant income and sales of other real estate owned. However, the recognition of these revenue streams did not change significantly upon adoption of Topic 606. Substantially all of the Company’s revenue is generated from contracts with customers. Noninterest revenue streams in-scope of Topic 606 are discussed below. Service Charges and Fees Service charges and fees consist of insufficient funds fees, continuous overdraft fees, monthly service charge fees, excessive transaction fees, stop payment fees and other deposit account related fees. Based on the Company's review of the depository contracts and the nature of these fees, the Company grouped the service charges and deposit-related fees embedded in the contracts into two distinct categories, either transactional or non-transactional fees. Transactional Fees With respect to transactional fees, the Company recognizes revenue at the time of service. The depository contracts with our customers stipulate that we will continue to provide services until the contract is terminated. Each party can immediately terminate the contract without compensating the other party for the termination (that is, there is no termination penalty). Since the duration of the depository contract doesn’t extend beyond the services already provided because either party can cancel the contract without compensating the other party, the relationship is, in effect, a day-to-day contract. Because the contract doesn’t extend beyond the services performed, the Company recognizes revenue at the time of service as there is no future contract under which to allocate consideration. Non-Transactional Fees With respect to monthly non-transactional fees, the Company recognizes revenue each month if it is entitled to the fee because the customer did not meet one of the agreed-upon criteria. Because the contract term does not extend beyond the services already provided (either party can immediately terminate the depository contract without compensating the other party), the Company will not need to make estimates about future monthly fees from a customer. Instead, the Company will recognize revenue for the maintenance fee if the customer does not meet one of the criteria and it would not recognize revenue for the maintenance fee if the customer meets one of the criteria. Other Noninterest Income Other noninterest income consists of debit card swipe fees, foreign ATM fees, merchant services revenue, referral income, check printing fees, early withdraw fees, collection fees, wire transfer fees, gain (loss) on sale of other real estate owned, and other miscellaneous fees. Debit card swipe fees are triggered by cardholder usage and are earned when the customer chooses “debit or credit” at the point of sale. The Bank receives a fee from the network (Interlink, STAR, and PLUS). The VISA international fee is earned when a customer uses a debit card overseas. ATM fees are primarily generated when a Company cardholder uses a non-Company ATM or a non-Company cardholder uses a Company ATM. Merchant services income mainly represents fees charged to merchants to process their debit and credit card transactions, in addition to account management fees. Referral fees are earned by either (i) matching a bank customer with a vendor’s credit card where the bank is paid a fee for each approved credit card application, or (ii) refer a customer to a third party for investment services. Check printing fees and other deposit account related fees are largely transactional based, and therefore, the Company’s performance obligation is satisfied, and related revenue recognized, when the services are rendered or upon completion. The Company records a gain or loss from the sale of OREO when control of the property transfers to the buyer, which generally occurs at the time of an executed deed. When the Company finances the sale of OREO to the buyer, the Company assesses whether the buyer is committed to perform their obligations under the contract and whether collectability of the transaction price is probable. Once these criteria are met, the OREO asset is derecognized and the gain or loss on sale is recorded upon the transfer of control of the property to the buyer. In determining the gain or loss on the sale, the Company adjusts the transaction price and related gain (loss) on sale if the Company financing is not at a market rate. The following table presents noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606, for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (Dollars in thousands) Noninterest Income In-scope of Topic 606: NSF/OD Fees $ 416 $ 328 $ 1,149 $ 1,113 Fees on deposit accounts 850 613 2,354 1,645 Service charges and fees 1,266 941 3,503 2,758 ATM and debit card income 261 551 1,571 1,762 Safe deposit box 19 18 70 67 Merchant revenue 214 188 633 531 Ancillary fees and income 195 88 457 266 CD custody income and fees 161 — 384 — Misc other income 100 134 581 3,922 Gain (loss) on sales of other real estate owned (70 ) (143 ) 43 (121 ) Noninterest Income (in-scope of Topic 606) $ 2,146 $ 1,777 $ 7,242 $ 9,185 Out-of-scope of Topic 606: Gain (loss) on sale of loans $ 142 $ 1,233 $ 92 $ 2,199 Gain (loss) on sale of fixed assets (24 ) 6 (13 ) 7 Loan and other fees 5,043 2,831 13,261 8,374 Bank-owned life insurance income 1,439 1,422 4,228 4,250 Income from resolution of acquired assets 202 466 603 1,548 Gain (loss) on investment securities (184 ) 690 (1,472 ) 1,722 Noninterest Income (out-of-scope of Topic 606) 6,618 6,648 16,699 18,100 Total noninterest income $ 8,764 $ 8,425 $ 23,941 $ 27,285 Contract Balances A contract asset balance occurs when an entity performs a service for a customer before the customer pays consideration (resulting in a contract receivable) or before payment is due (resulting in a contract asset). A contract liability balance is an entity’s obligation to transfer a service to a customer for which the entity has already received payment (or payment is due) from the customer. The Company’s noninterest revenue streams are largely based on transactional activity, or standard month-end revenue accruals. Consideration is often received immediately or shortly after the Company satisfies its performance obligation and revenue is recognized. The Company does not typically enter into long-term revenue contracts with customers, and therefore, does not experience significant contract balances. As of September 30, 2018 and December 31, 2017 , the Company did not have any significant contract balances. Contract Acquisition Costs In connection with the adoption of Topic 606, an entity is required to capitalize, and subsequently amortize into expense, certain incremental costs of obtaining a contract with a customer if these costs are expected to be recovered. The incremental costs of obtaining a contract are those costs that an entity incurs to obtain a contract with a customer that it would not have incurred if the contract had not been obtained (for example, sales commission). The Company utilizes the practical expedient which allows entities to immediately expense contract acquisition costs when the asset that would have resulted from capitalizing these costs would have been amortized in one year or less. Upon adoption of Topic 606, the Company did not capitalize any contract acquisition cost.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
General	General The accompanying unaudited consolidated financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all information and notes to the consolidated financial statements necessary for a complete presentation of financial position, results of operations, comprehensive income and cash flows in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”) and should be read in conjunction with the audited consolidated financial statements and the notes thereto for FCB Financial Holdings, Inc. (the “Company”) previously filed with the SEC in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . In the opinion of management, all adjustments, consisting of normal recurring adjustments, considered necessary for a fair presentation, have been included. The results of operations for the interim periods are not necessarily indicative of the results that may be expected for the full year or any other interim period.
Nature of Operations	Nature of Operations The Company is a national bank holding company with two wholly-owned subsidiaries: (i) Florida Community Bank, N.A., a national bank (“Florida Community Bank” or the “Bank”); and (ii) Floridian Custody Services, Inc. ("Custody Services"). Florida Community Bank, headquartered in Weston, Florida, offers a comprehensive range of traditional banking products and services to individual and corporate customers through 51 banking centers located in Florida as of September 30, 2018 . Custody Services, headquartered in Davie, Florida, provides clearing and custodian services to deposit brokers and their clients.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, Custody Services and Florida Community Bank, and the Bank’s subsidiaries, which consist of a group of real estate holding companies. Intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The Company’s financial reporting and accounting policies conform to U.S. GAAP. The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates subject to significant change include the allowance for loan losses, valuation of and accounting for acquired loans, the carrying value of OREO, the fair value of financial instruments, the valuation of goodwill and other intangible assets, acquisition-related fair value computations, stock-based compensation and deferred taxes.
Recent Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)”, which superseded the revenue recognition requirements in Topic 605, Revenue Recognition, and most industry-specific revenue recognition guidance throughout the Accounting Standards Codification. Under ASU No. 2014-09, revenue should be recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying the guidance, an entity should 1) identify the contract(s) with a customer, 2) identify the performance obligations in the contract, 3) determine the transaction price, 4) allocate the transaction price to the performance obligations in the contract, and 5) recognize revenue when the entity satisfies a performance obligation. This guidance should be applied to all contracts with customers except those that are within the scope of other standards. This ASU became effective for the quarter ended March 31, 2018. The Company elected to adopt the new guidance under the modified retrospective approach. Since the Company's revenue is comprised primarily of net interest income from financial instruments that are within the scope of other standards, including loans and securities, the new guidance did not have a material impact upon adoption. In addition, the adoption of this guidance did not result in any material changes to the method of revenue recognition on the components of noninterest income. Accordingly, the adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In May 2016, the FASB issued ASU No. 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing.” The amendments in this ASU do not change the core principle of the guidance in Topic 606. Rather, the amendments in this ASU clarify the following two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance, while retaining the related principles for those areas. The amendments in this ASU affect the guidance in ASU 2014-09, “Revenue from Contracts with Customers (Topic 606)”. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In May 2016, the FASB issued ASU No. 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients.” The amendments in this ASU do not change the core principle of the guidance in Topic 606. Rather, the amendments in this ASU clarify the guidance on assessing collectability, presentation of sales taxes, noncash consideration, and completed contracts and contract modifications at transition. The amendments in this ASU affect the guidance in ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)". This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In January 2016, the FASB issued ASU No. 2016-01, “Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” which: • Requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. • Simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment. When a qualitative assessment indicates that impairment exists, an entity is required to measure the investment at fair value. • Eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet. • Requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes. • Requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. • Requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements. • Clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. An entity should apply the amendments by means of a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. The amendments related to equity securities without readily determinable fair values (including disclosure requirements) should be applied prospectively to equity investments that exist as of the date of adoption of the ASU. This ASU became effective the for the quarter ended March 31, 2018. As of January 1, 2018, the Company had equity securities in a net pre-tax unrealized gain position of $1.6 million for which $1.0 million , the tax effected balance, was reclassified from other comprehensive income to beginning retained earnings at adoption. In August 2016, the FASB issued ASU No. 2016-15, "Statement of cash flows (Topic 230): Classification of certain cash receipts and cash payments." The objective of this guidance is to reduce the diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows under Topic 230, Statement of Cash Flows, and other Topics. This ASU addresses the following eight specific cash flow issues: Debt prepayment or debt extinguishment costs; settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; contingent consideration payments made after a business combination; proceeds from the settlement of insurance claims; proceeds from the settlement of corporate-owned life insurance policies (COLIs) (including bank-owned life insurance policies (BOLIs)); distributions received from equity method investees; beneficial interests in securitization transactions; and separately identifiable cash flows and application of the predominance principle. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In October 2016, the FASB issued ASU No. 2016-16, "Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory." The objective of issuing this ASU is to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party. This prohibition on recognition is an exception to the principle of comprehensive recognition of current and deferred income taxes in GAAP. As such, the Board decided that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Consequently, the amendments in this guidance eliminate the exception for an intra-entity transfer of an asset other than inventory. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In November 2016, the FASB issued ASU No. 2016-18, "Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force)." The amendments in this ASU require that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in this ASU do not provide a definition of restricted cash or restricted cash equivalents. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In February 2017, the FASB issued ASU No. 2017-05, "Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets." The FASB is issuing this ASU to clarify the scope of Subtopic 610-20, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets, and to add guidance for partial sales of nonfinancial assets. The amendments in this ASU will require all entities to account for the derecognition of a business or nonprofit activity in accordance with Topic 810. The amendments also eliminate several accounting differences between transactions involving assets and transactions involving businesses. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In May 2017, the FASB issued ASU No. 2017-09, "Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting." This ASU provides clarity when applying the guidance in Topic 718, specifically relating to a modification of a share-based payment award. Entities should treat changes as modifications unless the fair value, vesting conditions, and classification of the modified awards are unchanged from the conditions immediately before the change. This ASU became effective for the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In August 2017, the FASB issued ASU No. 2017-12, "Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities." This ASU improves the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements and makes certain targeted improvements to simplify the application of the hedge accounting guidance in current GAAP. The amendments in this update better align an entity's risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and presentation of hedge results. The Company early adopted ASU 2017-12 during the quarter ended March 31, 2018. The adoption of this guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. In February 2018, the FASB issued ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” This ASU seeks to help entities reclassify certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017 (Tax Reform Act), enacted on December 22, 2017. ASU 2018-02 was issued in response to concerns regarding current guidance in GAAP that requires deferred tax liabilities and assets to be adjusted for the effect of a change in tax laws or rates with the effect included in income from continuing operations in the reporting period that includes the enactment date, even in situations in which the related income tax effects of items in accumulated other comprehensive income were originally recognized in other comprehensive income, rather than net income, and as a result the stranded tax effects would not reflect the appropriate tax rate. ASU 2018-02 allows an entity to make a reclassification from accumulated other comprehensive income to retained earnings for the stranded tax effects, which is the difference between the historical corporate income tax rate of 35.0% and the newly enacted corporate income tax rate of 21.0%. The amendments in this ASU are effective for fiscal years, and interim periods within those years, beginning after December 31, 2018; however, public business entities are allowed to early adopt ASU 2018-02 in any interim period for which the financial statements have not yet been issued. ASU 2018-02 may be applied either at the beginning of the period (annual or interim) of adoption or retrospectively to each of the period(s) in which the effect of the change in the U.S. federal corporate tax rate in the Tax Reform Act is recognized. As a result of the re-measurement of the Company's deferred tax assets following the enactment of the Tax Reform Act, accumulated other comprehensive income included $1.7 million of stranded tax effects at December 31, 2017. The Company early adopted ASU 2018-02 during the quarter ended March 31, 2018 and made the election to reclassify the stranded tax effects from accumulated other comprehensive income to retained earnings at the beginning of the period of adoption. Recently Issued Accounting Pronouncements In January 2018, the FASB issued ASU No. 2018-01, "Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842." This ASU provides an optional transition practical expedient to not evaluate under Topic 842, existing or expired land easements that were not previously accounted for as leases under the current leases guidance in Topic 840. An entity that elects this practical expedient should evaluate new or modified land easements under Topic 842 beginning at the date that the entity adopts Topic 842. An entity that does not elect this practical expedient should evaluate all existing or expired land easements in connection with the adoption of the new lease requirements in Topic 842 to assess whether they meet the definition of a lease. The amendments in this guidance affect the amendments in ASU 2016-02, which are not yet effective but may be early adopted. The effective date and transition requirements for the amendments are the same as the effective date and transition requirements in ASU 2016-02. An entity that early adopted Topic 842 should apply the amendments in this ASU upon issuance. Management does not intend to early adopt this guidance. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In June 2018, the FASB issued ASU 2018-07, "Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting." The amendments of this ASU expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. 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 are effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In July 2018, the FASB issued ASU 2018-11, "Leases (Topic 842): Targeted Improvements." The amendments of this ASU provide another transition method for the adoption of the new leases standard. Currently, entities are required to adopt the new leases standard using a modified retrospective transition method. The amendments of this ASU provide another transition method by allowing entities to initially apply the new leases standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Additionally, this ASU also provides lessors a practical expedient to not separate nonlease components from the associated lease component, similar to the expedient provided for lessees. The amendments related to separating components of a contract affect the amendments in ASU 2016-02, which are not yet effective but can be early adopted. For entities that have not adopted Topic 842 before the issuance of this ASU, the effective date and transition requirements for the amendments in this ASU related to separating components of a contract are the same as the effective date and transition requirements in ASU 2016-02. Management does not intend to early adopt this guidance. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In August 2018, the FASB issued ASU 2018-13, "Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement." The amendments of this ASU modify the disclosure requirements about recurring or nonrecurring fair value measurements required under Topic 820, Fair Value Measurement, and require additional disclosures related to unrealized gains and losses included in other comprehensive income. The amendments in this ASU are effective for all entities for fiscal years, and interim periods within those fiscal years, 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 ASU. An entity is permitted to early adopt any removed or modified disclosures upon issuance of this ASU and delay adoption of the additional disclosures until their effective date. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In August 2018, the FASB issued ASU 2018-15, "Intangibles - Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract." The amendments in this ASU align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The amendments in this ASU are effective for public business entities for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption of the amendments in this ASU is permitted, including adoption in any interim period, for all entities. The amendments in this ASU should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company does not believe the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows.

Business Acquisitions (Tables)

Business Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The following table presents a summary of the assets acquired and liabilities assumed in the Floridian acquisition recorded at fair value: Acquisition Date Fair Value Measurement Period Adjustments Adjusted Acquisition Date Fair Value (Dollars in thousands) Consideration transferred: Common stock issued $ 94,122 $ — $ 94,122 Liability incurred related to settlement of outstanding stock options 5,198 — 5,198 Total consideration transferred 99,320 — 99,320 Fair value of assets acquired: Cash and cash equivalents 16,699 (43 ) 16,656 Investment securities 38,772 — 38,772 Loans 425,894 — 425,894 Other real estate owned 113 (2 ) 111 Core deposit intangible 4,580 — 4,580 Fixed assets 3,425 — 3,425 Deferred tax asset, net 5,043 (239 ) 4,804 Bank-owned life insurance 10,489 — 10,489 Other assets 2,678 (574 ) 2,104 Total identifiable assets acquired 507,693 (858 ) 506,835 Fair value of liabilities assumed: Deposits 382,333 — 382,333 FHLB advances and other borrowings 73,389 — 73,389 Other liabilities 11,231 (1,113 ) 10,118 Total liabilities assumed 466,953 (1,113 ) 465,840 Fair value of net assets acquired 40,740 255 40,995 Goodwill resulting from acquisition $ 58,580 $ (255 ) $ 58,325

Investment Securities (Tables)

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Cost, Gross Unrealized Gains and Losses and Approximate Fair Values of Securities Available for Sale	The amortized cost, gross unrealized gains and losses and approximate fair values of available for sale debt securities are as follows: Amortized Cost Unrealized Fair Value September 30, 2018 Gains Losses (Dollars in thousands) Available for sale debt securities: U.S. Government agencies and sponsored enterprises obligations $ 86,941 $ — $ 2,709 $ 84,232 U.S. Government agencies and sponsored enterprises mortgage-backed securities 627,668 9 23,519 604,158 State and municipal obligations 24,485 66 1,669 22,882 Asset-backed securities 780,250 330 2,258 778,322 Corporate bonds and other debt securities 791,130 7,609 12,630 786,109 Total available for sale debt securities $ 2,310,474 $ 8,014 $ 42,785 $ 2,275,703 Amortized Cost Unrealized Fair Value December 31, 2017 Gains Losses (Dollars in thousands) Available for sale debt securities: (1) U.S. Government agencies and sponsored enterprises obligations $ 43,471 $ 38 $ 671 $ 42,838 U.S. Government agencies and sponsored enterprises mortgage-backed securities 600,310 1,716 6,789 595,237 State and municipal obligations 26,766 125 719 26,172 Asset-backed securities 608,340 2,306 100 610,546 Corporate bonds and other debt securities 738,994 18,222 1,313 755,903 Total available for sale debt securities $ 2,017,881 $ 22,407 $ 9,592 $ 2,030,696 (1) To allow for improved comparability, prior year presentation has been modified to remove preferred stock and other equity securities in connection with the adoption of ASU 2016-01.
Schedule of Amortized Cost and Estimated Fair Value of Securities Available for Sale	The amortized cost and estimated fair value of available for sale debt securities, by contractual maturity, are as follows: September 30, 2018 Amortized Cost Fair Value (Dollars in thousands) Available for sale debt securities: Due in one year or less $ 57,430 $ 57,475 Due after one year through five years 290,655 287,076 Due after five years through ten years 138,696 135,574 Due after ten years 328,834 328,866 U.S. Government agencies and sponsored enterprises obligations, mortgage-backed securities and asset-backed securities 1,494,859 1,466,712 Total available for sale debt securities $ 2,310,474 $ 2,275,703
Summary of Estimated Fair Values and Gross Unrealized Losses on Investment Securities Available for Sale	The following tables present the estimated fair values and gross unrealized losses on available for sale debt securities, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position as of the periods presented: Less than 12 Months 12 Months or More Total September 30, 2018 Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss (Dollars in thousands) Available for sale debt securities: U.S. Government agencies and sponsored enterprises obligations $ 51,529 $ 906 $ 32,703 $ 1,803 $ 84,232 $ 2,709 U.S. Government agencies and sponsored enterprises mortgage-backed securities 279,436 8,128 300,994 15,391 580,430 23,519 State and municipal obligations — — 20,772 1,669 20,772 1,669 Asset-backed securities 348,117 2,196 7,002 62 355,119 2,258 Corporate bonds and other debt securities 391,610 8,486 91,574 4,144 483,184 12,630 Total available for sale debt securities $ 1,070,692 $ 19,716 $ 453,045 $ 23,069 $ 1,523,737 $ 42,785 Less than 12 Months 12 Months or More Total December 31, 2017 Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss (Dollars in thousands) Available for sale debt securities: (1) U.S. Government agencies and sponsored enterprises obligations $ 31,518 $ 268 $ 7,157 $ 403 $ 38,675 $ 671 U.S. Government agencies and sponsored enterprises mortgage-backed securities 207,735 1,836 175,810 4,953 383,545 6,789 State and municipal obligations 192 2 23,813 717 24,005 719 Asset-backed securities 36,542 100 — — 36,542 100 Corporate bonds and other debt securities 186,052 1,240 10,842 73 196,894 1,313 Total available for sale debt securities $ 462,039 $ 3,446 $ 217,622 $ 6,146 $ 679,661 $ 9,592 (1) To allow for improved comparability, prior year presentation has been modified to remove preferred stock and other equity securities in connection with the adoption of ASU 2016-01.
Summary of Gross Realized Gains and Losses on Sale of Securities Available for Sale	Gross realized gains and losses on the sale of available for sale debt securities are shown below. The cost of securities sold is based on the specific identification method. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (Dollars in thousands) Gross realized gains $ 2 $ 1,251 $ 147 $ 1,945 Gross realized losses (1,248 ) (1,533 ) (1,254 ) (2,739 ) Net realized gains (losses) $ (1,246 ) $ (282 ) $ (1,107 ) $ (794 )

Loans, Net (Tables)

Loans, Net (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Schedule of Loans by Portfolio and Segment	The following tables summarize the Company’s loans by portfolio and segment as of the periods presented, net of deferred fees, costs, premiums and discounts: September 30, 2018 ASC 310-30 Loans Non-ASC 310-30 Loans New Loans (1) Total (Dollars in thousands) Real estate loans: Commercial real estate $ 133,778 $ 104,364 $ 2,528,748 $ 2,766,890 Owner-occupied commercial real estate — 81,408 1,134,793 1,216,201 1-4 single family residential 32,240 148,659 2,245,139 2,426,038 Construction, land and development 28,590 36,881 754,972 820,443 Home equity loans and lines of credit — 40,131 59,729 99,860 Total real estate loans 194,608 411,443 6,723,381 7,329,432 Other loans: Commercial and industrial 19,503 46,643 1,902,045 1,968,191 Consumer 1,259 13,950 3,976 19,185 Total other loans 20,762 60,593 1,906,021 1,987,376 Total loans held in portfolio $ 215,370 $ 472,036 $ 8,629,402 $ 9,316,808 Allowance for loan losses (53,148 ) Loans held in portfolio, net $ 9,263,660 December 31, 2017 ASC 310-30 Loans Non-ASC 310-30 Loans New Loans (1) Total (Dollars in thousands) Real estate loans: Commercial real estate $ 104,335 $ 37,736 $ 2,103,788 $ 2,245,859 Owner-occupied commercial real estate — 16,100 987,781 1,003,881 1-4 single family residential 27,513 57,695 2,185,362 2,270,570 Construction, land and development 13,167 5,889 684,462 703,518 Home equity loans and lines of credit — 34,589 59,636 94,225 Total real estate loans 145,015 152,009 6,021,029 6,318,053 Other loans: Commercial and industrial 12,631 5,062 1,634,372 1,652,065 Consumer 1,423 259 5,984 7,666 Total other loans 14,054 5,321 1,640,356 1,659,731 Total loans held in portfolio $ 159,069 $ 157,330 $ 7,661,385 $ 7,977,784 Allowance for loan losses (47,145 ) Loans held in portfolio, net $ 7,930,639 (1) Balance includes $(9.2) million and $(6.6) million of net deferred fees, costs, and premium and discount as of September 30, 2018 and December 31, 2017 , respectively.
Summary of Changes in Accretable Discount for ASC 310-30 Loans	Changes in accretable discount for ASC 310-30 loans for the nine months ended September 30, 2018 and 2017 , were as follows: Nine Months Ended September 30, 2018 2017 (Dollars in thousands) Balance at January 1, $ 41,162 $ 60,990 Additions to accretable discount from FLCB acquisition 14,393 — Accretion (10,857 ) (13,965 ) Reclassifications from (to) non-accretable difference 3,417 (2,747 ) Balance at September 30, $ 48,115 $ 44,278

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Summary of Changes in Allowance for Loan Losses by Loan Class and Portfolio Segment	Commercial Real Estate Owner- Occupied Commercial Real Estate 1-4 Single Family Residential Construction, Land and Development Home Equity Loans and Lines of Credit Commercial and Industrial Consumer Total (Dollars in thousands) Balance at July 1, 2018 $ 15,381 $ 3,946 $ 7,310 $ 4,076 $ 704 $ 18,934 $ 219 $ 50,570 Provision (credit) for ASC 310-30 loans (26 ) (3 ) 14 (115 ) — (66 ) (16 ) (212 ) Provision (credit) for non-ASC 310-30 loans (8 ) (3 ) (35 ) 71 2 129 — 156 Provision (credit) for New loans 560 (141 ) (333 ) 1,228 (24 ) 994 (8 ) 2,276 Provision (credit) for Unallocated — — — — — — — — Total provision 526 (147 ) (354 ) 1,184 (22 ) 1,057 (24 ) 2,220 Charge-offs for ASC 310-30 loans (1 ) — (22 ) — — — (4 ) (27 ) Charge-offs for non-ASC 310-30 loans (118 ) — — — — — — (118 ) Charge-offs for New loans — — — — — — — — Total charge-offs (119 ) — (22 ) — — — (4 ) (145 ) Recoveries for ASC 310-30 loans 366 3 1 93 — 7 — 470 Recoveries for non-ASC 310-30 loans — — 23 — — — — 23 Recoveries for New loans — 9 — — — — — 9 Total recoveries 366 12 24 93 — 7 — 502 Ending ALL balance ASC 310-30 loans 1,556 — 8 103 — 80 119 1,866 Non-ASC 310-30 loans 188 51 144 130 204 447 3 1,167 New loans 14,410 3,760 6,806 5,121 478 19,471 69 50,115 Unallocated — — — — — — — — Balance at September 30, 2018 $ 16,154 $ 3,811 $ 6,958 $ 5,354 $ 682 $ 19,998 $ 191 $ 53,148 Commercial Real Estate Owner- Occupied Commercial Real Estate 1-4 Single Family Residential Construction, Land and Development Home Equity Loans and Lines of Credit Commercial and Industrial Consumer Total (Dollars in thousands) Balance at July 1, 2017 $ 12,155 $ 3,286 $ 8,749 $ 4,713 $ 884 $ 11,296 $ 251 $ 41,334 Provision (credit) for ASC 310-30 loans (41 ) — — (38 ) — (38 ) (8 ) (125 ) Provision (credit) for non-ASC 310-30 loans 30 (1 ) (49 ) (2 ) (227 ) (56 ) 1 (304 ) Provision (credit) for New loans 943 342 (335 ) (113 ) 42 933 (12 ) 1,800 Provision (credit) for Unallocated — — — — — — — 1,500 Total provision 932 341 (384 ) (153 ) (185 ) 839 (19 ) 2,871 Charge-offs for ASC 310-30 loans — — — — — — — — Charge-offs for non-ASC 310-30 loans (30 ) — (9 ) — — (3 ) — (42 ) Charge-offs for New loans — — — — (3 ) — — (3 ) Total charge-offs (30 ) — (9 ) — (3 ) (3 ) — (45 ) Recoveries for ASC 310-30 loans 27 — — — — 70 — 97 Recoveries for non-ASC 310-30 loans — — 30 — — 4 — 34 Recoveries for New loans — — — — — — — — Total recoveries 27 — 30 — — 74 — 131 Ending ALL balance ASC 310-30 loans 1,664 — 25 147 — 200 152 2,188 Non-ASC 310-30 loans 331 64 214 36 224 311 7 1,187 New loans 11,089 3,563 8,147 4,377 472 11,695 73 39,416 Unallocated — — — — — — — 1,500 Balance at September 30, 2017 $ 13,084 $ 3,627 $ 8,386 $ 4,560 $ 696 $ 12,206 $ 232 $ 44,291 Commercial Real Estate Owner- Occupied Commercial Real Estate 1-4 Single Family Residential Construction, Land and Development Home Equity Loans and Lines of Credit Commercial and Industrial Consumer Total (Dollars in thousands) Balance at January 1, 2018 $ 13,870 $ 3,365 $ 7,978 $ 4,345 $ 674 $ 15,141 $ 272 $ 47,145 Provision (credit) for ASC 310-30 loans (102 ) (3 ) (15 ) (149 ) — (53 ) (15 ) (337 ) Provision (credit) for non-ASC 310-30 loans (32 ) (4 ) (62 ) 94 5 170 (3 ) 168 Provision (credit) for New loans 2,315 441 (963 ) 957 3 4,769 (52 ) 7,470 Provision (credit) for Unallocated — — — — — — — (1,500 ) Total provision 2,181 434 (1,040 ) 902 8 4,886 (70 ) 5,801 Charge-offs for ASC 310-30 loans (156 ) — (22 ) — — (17 ) (11 ) (206 ) Charge-offs for non-ASC 310-30 loans (118 ) — — — — (36 ) — (154 ) Charge-offs for New loans — — — — — — — — Total charge-offs (274 ) — (22 ) — — (53 ) (11 ) (360 ) Recoveries for ASC 310-30 loans 366 3 19 106 — 24 — 518 Recoveries for non-ASC 310-30 loans — — 23 — — — — 23 Recoveries for New loans 11 9 — — — — — 20 Total recoveries 377 12 42 106 — 24 — 561 Ending ALL balance ASC 310-30 loans 1,556 — 8 103 — 80 119 1,866 Non-ASC 310-30 loans 188 51 144 130 204 447 3 1,167 New loans 14,410 3,760 6,806 5,121 478 19,471 69 50,115 Unallocated — — — — — — — — Balance at September 30, 2018 $ 16,154 $ 3,811 $ 6,958 $ 5,354 $ 682 $ 19,998 $ 191 $ 53,148 Commercial Real Estate Owner- Occupied Commercial Real Estate 1-4 Single Family Residential Construction, Land and Development Home Equity Loans and Lines of Credit Commercial and Industrial Consumer Total (Dollars in thousands) Balance at January 1, 2017 $ 10,123 $ 2,597 $ 7,379 $ 4,677 $ 648 $ 12,245 $ 228 37,897 Provision (credit) for ASC 310-30 loans (623 ) — 31 (49 ) — (118 ) (92 ) (851 ) Provision (credit) for non-ASC 310-30 loans (15 ) 3 (48 ) (11 ) (12 ) (66 ) (28 ) (177 ) Provision (credit) for New loans 3,728 1,027 1,098 (14 ) 70 253 (5 ) 6,157 Provision (credit) for Unallocated — — — — — — — 1,500 Total provision 3,090 1,030 1,081 (74 ) 58 69 (125 ) 6,629 Charge-offs for ASC 310-30 loans (9 ) — (35 ) (43 ) — (29 ) — (116 ) Charge-offs for non-ASC 310-30 loans (30 ) — (69 ) — (7 ) (3 ) — (109 ) Charge-offs for New loans (131 ) — — — (3 ) (150 ) — (284 ) Total charge-offs (170 ) — (104 ) (43 ) (10 ) (182 ) — (509 ) Recoveries for ASC 310-30 loans 41 — — — — 70 100 211 Recoveries for non-ASC 310-30 loans — — 30 — — 4 29 63 Recoveries for New loans — — — — — — — — Total recoveries 41 — 30 — — 74 129 274 Ending ALL balance ASC 310-30 loans 1,664 — 25 147 — 200 152 2,188 Non-ASC 310-30 loans 331 64 214 36 224 311 7 1,187 New loans 11,089 3,563 8,147 4,377 472 11,695 73 39,416 Unallocated — — — — — — — 1,500 Balance at September 30, 2017 $ 13,084 $ 3,627 $ 8,386 $ 4,560 $ 696 $ 12,206 $ 232 $ 44,291
Summary of Aging Analysis of Recorded Investment for Loans by Portfolio and Segment	The following tables present an aging analysis of the recorded investment for delinquent loans by portfolio and segment (excluding loans accounted for under ASC 310-30): Accruing September 30, 2018 30 to 59 Days Past Due 60 to 89 Days Past Due 90 Days or More Past Due Non- Accrual Total (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ 7 $ — $ 460 $ 467 Owner-occupied commercial real estate — 827 — 2,440 3,267 1-4 single family residential 1,993 334 — 4,157 6,484 Construction, land and development — — — — — Home equity loans and lines of credit — — — 126 126 Total real estate loans 1,993 1,168 — 7,183 10,344 Other loans: Commercial and industrial 212 152 — 155 519 Consumer 24 — — — 24 Total other loans 236 152 — 155 543 Total new loans $ 2,229 $ 1,320 $ — $ 7,338 $ 10,887 Acquired loans: Real estate loans: Commercial real estate $ — $ — $ — $ 3,615 $ 3,615 Owner-occupied commercial real estate — — — 486 486 1-4 single family residential — 96 — 1,677 1,773 Construction, land and development — — — — — Home equity loans and lines of credit 716 — — 2,543 3,259 Total real estate loans 716 96 — 8,321 9,133 Other loans: Commercial and industrial 64 24 — 2,816 2,904 Consumer — — — — — Total other loans 64 24 — 2,816 2,904 Total acquired loans $ 780 $ 120 $ — $ 11,137 $ 12,037 Accruing December 31, 2017 30 to 59 Days Past Due 60 to 89 Days Past Due 90 Days or More Past Due Non- Accrual Total (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ 324 $ — $ — $ — $ 324 Owner-occupied commercial real estate 843 150 — — 993 1-4 single family residential 1,179 1,310 — 3,167 5,656 Construction, land and development — — — — — Home equity loans and lines of credit — — — 126 126 Total real estate loans 2,346 1,460 — 3,293 7,099 Other loans: Commercial and industrial 4,980 2,167 — — 7,147 Consumer — — — — — Total other loans 4,980 2,167 — — 7,147 Total new loans $ 7,326 $ 3,627 $ — $ 3,293 $ 14,246 Acquired Loans: Real estate loans: Commercial real estate $ 360 $ — $ — $ 3,893 $ 4,253 Owner-occupied commercial real estate 290 — — 494 784 1-4 single family residential 892 44 — 1,331 2,267 Construction, land and development — — — — — Home equity loans and lines of credit 1,128 — — 1,720 2,848 Total real estate loans 2,670 44 — 7,438 10,152 Other loans: Commercial and industrial 101 — — 394 495 Consumer — — — — — Total other loans 101 — — 394 495 Total acquired loans $ 2,771 $ 44 $ — $ 7,832 $ 10,647
Summary of Commercial Non-ASC 310-30 and New Loans by Key Indicators of Credit Quality	The following tables summarize the Company’s commercial Non-ASC 310-30 and New loans by key indicators of credit quality. Loans accounted for under ASC 310-30 are excluded from the following analysis because their related allowance is determined by loan pool performance: September 30, 2018 Pass Special Mention Substandard Doubtful (Dollars in thousands) New loans: Commercial real estate $ 2,515,933 $ 9,325 $ 3,490 $ — Owner-occupied commercial real estate 1,131,769 584 2,440 — Construction, land and development 754,972 — — — Commercial and industrial 1,868,553 21,991 11,501 — Total new loans $ 6,271,227 $ 31,900 $ 17,431 $ — Acquired loans: Commercial real estate $ 100,413 $ — $ 3,951 $ — Owner-occupied commercial real estate 80,835 — 573 — Construction, land and development 36,881 — — — Commercial and industrial 42,447 1,024 3,172 — Total acquired loans $ 260,576 $ 1,024 $ 7,696 $ — December 31, 2017 Pass Special Substandard Doubtful (Dollars in thousands) New loans: Commercial real estate $ 2,095,560 $ 6,066 $ 2,162 $ — Owner-occupied commercial real estate 987,781 — — — Construction, land and development 684,462 — — — Commercial and industrial 1,617,462 16,910 — — Total new loans $ 5,385,265 $ 22,976 $ 2,162 $ — Acquired loans: Commercial real estate $ 33,496 $ — $ 4,240 $ — Owner-occupied commercial real estate 15,607 — 493 — Construction, land and development 5,889 — — — Commercial and industrial 4,324 — 738 — Total acquired loans $ 59,316 $ — $ 5,471 $ —
Summary of Loans Based on Method for Determining Allowance	The following tables show the Company’s investment in loans disaggregated based on the method of evaluating impairment: Loans - Recorded Investment Allowance for Credit Loss September 30, 2018 Individually Evaluated for Impairment Collectively Evaluated for Impairment ASC 310- 30 Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment ASC 310- 30 Loans (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ 2,528,748 $ — $ — $ 14,410 $ — Owner-occupied commercial real estate 2,899 1,131,894 — — 3,760 — 1-4 single family residential 1,637 2,243,502 — — 6,806 — Construction, land and development — 754,972 — — 5,121 — Home equity loans and lines of credit 126 59,603 — 63 415 — Total real estate loans $ 4,662 $ 6,718,719 $ — $ 63 $ 30,512 $ — Other loans: Commercial and industrial $ 16,708 $ 1,885,337 $ — $ 1,593 $ 17,878 $ — Consumer — 3,976 — — 69 — Total other loans $ 16,708 $ 1,889,313 $ — $ 1,593 $ 17,947 $ — Acquired loans: Real estate loans: Commercial real estate $ 3,396 $ 100,968 $ 133,778 $ — $ 188 $ 1,556 Owner-occupied commercial real estate — 81,408 — — 51 — 1-4 single family residential 267 148,392 32,240 — 144 8 Construction, land and development — 36,881 28,590 — 130 103 Home equity loans and lines of credit 494 39,637 — — 204 — Total real estate loans $ 4,157 $ 407,286 $ 194,608 $ — $ 717 $ 1,667 Other loans: Commercial and industrial $ 3,442 $ 43,201 $ 19,503 $ 394 $ 53 $ 80 Consumer — 13,950 1,259 — 3 119 Total other loans $ 3,442 $ 57,151 $ 20,762 $ 394 $ 56 $ 199 Total Loans: Unallocated $ — $ 9,316,808 $ — $ — $ — $ — Loans - Recorded Investment Allowance for Credit Loss December 31, 2017 Individually Evaluated for Impairment Collectively Evaluated for Impairment ASC 310- 30 Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment ASC 310- 30 Loans (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ 2,103,788 $ — $ — $ 12,084 $ — Owner-occupied commercial real estate — 987,781 — — 3,310 — 1-4 single family residential 1,096 2,184,266 — — 7,769 — Construction, land and development — 684,462 — — 4,164 — Home equity loans and lines of credit 130 59,506 — 66 409 — Total real estate loans $ 1,226 $ 6,019,803 $ — $ 66 $ 27,736 $ — Other loans: Commercial and industrial $ — $ 1,634,372 $ — $ — $ 14,702 $ — Consumer — 5,984 — — 121 — Total other loans $ — $ 1,640,356 $ — $ — $ 14,823 $ — Acquired Loans: Real estate loans: Commercial real estate $ 3,893 $ 33,843 $ 104,335 $ 129 $ 209 $ 1,448 Owner-occupied commercial real estate — 16,100 — — 55 — 1-4 single family residential 267 57,428 27,513 — 184 25 Construction, land and development — 5,889 13,167 — 36 145 Home equity loans and lines of credit 495 34,094 — — 199 — Total real estate loans $ 4,655 $ 147,354 $ 145,015 $ 129 $ 683 $ 1,618 Other loans: Commercial and industrial $ 272 $ 4,790 $ 12,631 $ 272 $ 41 $ 126 Consumer — 259 1,423 — 6 145 Total other loans $ 272 $ 5,049 $ 14,054 $ 272 $ 47 $ 271 Total Loans: Unallocated $ — $ 7,977,784 $ — $ — $ 1,500 $ —
Summary of Company's Impaired Loans Evaluated for Specific Reserves	The following tables set forth certain information regarding the Company’s impaired loans (excluding loans accounted for under ASC 310-30) that were evaluated for specific reserves: Impaired Loans - With Allowance Impaired Loans - With no Allowance September 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ — $ — $ 459 $ 470 Owner-occupied commercial real estate — — — 2,440 2,440 1-4 single family residential — — — 1,637 1,641 Construction, land and development — — — — — Home equity loans and lines of credit 63 66 63 63 63 Total real estate loans $ 63 $ 66 $ 63 $ 4,599 $ 4,614 Other loans: Commercial and industrial $ 16,708 $ 16,708 $ 1,593 $ — $ — Consumer — — — — — Total other loans $ 16,708 $ 16,708 $ 1,593 $ — $ — Acquired loans: Real estate loans: Commercial real estate $ — $ — $ — $ 3,396 $ 4,991 Owner-occupied commercial real estate — — — — — 1-4 single family residential — — — 267 267 Construction, land and development — — — — — Home equity loans and lines of credit — — — 495 495 Total real estate loans $ — $ — $ — $ 4,158 $ 5,753 Other loans: Commercial and industrial $ 394 $ 394 $ 394 $ 3,047 $ 6,948 Consumer — — — — — Total other loans $ 394 $ 394 $ 394 $ 3,047 $ 6,948 Impaired Loans - With Allowance Impaired Loans - With no Allowance December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance (Dollars in thousands) New loans: Real estate loans: Commercial real estate $ — $ — $ — $ — $ — Owner-occupied commercial real estate — — — — — 1-4 single family residential — — — 1,096 1,096 Construction, land and development — — — — — Home equity loans and lines of credit 66 66 66 63 63 Total real estate loans $ 66 $ 66 $ 66 $ 1,159 $ 1,159 Other loans: Commercial and industrial $ — $ — $ — $ — $ — Consumer — — — — — Total other loans $ — $ — $ — $ — $ — Acquired loans: Real estate loans: Commercial real estate $ 336 $ 347 $ 129 $ 3,557 $ 4,991 Owner-occupied commercial real estate — — — — — 1-4 single family residential — — — 267 267 Construction, land and development — — — — — Home equity loans and lines of credit — — — 495 495 Total real estate loans $ 336 $ 347 $ 129 $ 4,319 $ 5,753 Other loans: Commercial and industrial $ 272 $ 272 $ 272 $ — $ — Consumer — — — — — Total other loans $ 272 $ 272 $ 272 $ — $ —
Summary of Impaired Loans Average Recorded Investment and Interest Income Recognized	The following tables present the average recorded investment and interest income recognized during the period subsequent to impairment on loans individually evaluated for impairment: Three Months Ended September 30, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with no related allowance: Real estate loans: Commercial real estate $ 3,887 $ — $ 3,629 $ — Owner-occupied commercial real estate 2,440 — — — 1-4 single family residential 1,903 — 1,363 — Construction, land and development — — — — Home equity loans and lines of credit 558 — 534 — Total real estate loans $ 8,788 $ — $ 5,526 $ — Other loans: Commercial and industrial $ 3,038 $ — $ — $ — Consumer — — — — Total other loans $ 3,038 $ — $ — $ — Impaired loans with an allowance: Real estate loans: Commercial real estate $ — $ — $ 336 $ — Owner-occupied commercial real estate — — — — 1-4 single family residential — — 497 — Construction, land and development — — — — Home equity loans and lines of credit 63 — 66 — Total real estate loans $ 63 $ — $ 899 $ — Other loans: Commercial and industrial $ 17,102 $ — $ 299 $ — Consumer — — — — Total other loans $ 17,102 $ — $ 299 $ — Nine Months Ended September 30, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with no related allowance: Real estate loans: Commercial real estate $ 3,636 $ — $ 3,677 $ — Owner-occupied commercial real estate 1,058 — — — 1-4 single family residential 1,537 — 1,174 — Construction, land and development — — — — Home equity loans and lines of credit 558 — 750 — Total real estate loans $ 6,789 $ — $ 5,601 $ — Other loans: Commercial and industrial $ 1,284 $ — $ — $ — Consumer — — — — Total other loans $ 1,284 $ — $ — $ — Impaired loans with an allowance: Real estate loans: Commercial real estate $ — $ — $ 529 $ — Owner-occupied commercial real estate — — — — 1-4 single family residential — — 509 — Construction, land and development — — — — Home equity loans and lines of credit 65 — 201 — Total real estate loans $ 65 $ — $ 1,239 $ — Other loans: Commercial and industrial $ 11,528 $ — $ 333 $ — Consumer — — — — Total other loans $ 11,528 $ — $ 333 $ —

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill and Other Intangible Assets	Goodwill and other intangible assets are summarized as follows: September 30, 2018 December 31, 2017 (Dollars in thousands) Goodwill $ 139,529 $ 81,204 Core deposit intangible 18,950 14,370 Less: Accumulated amortization (11,737 ) (10,702 ) Net core deposit intangible $ 7,213 $ 3,668
Schedule of Estimated Amortization Expense for the Next Five Fiscal Years	The estimated amount of amortization expense for core deposit intangible assets to be recognized for the remainder of 2018 through 2022 is as follows: Remainder of 2018 2019 2020 2021 2022 (Dollars in thousands) Core deposit intangible $ 370 $ 1,481 $ 968 $ 818 $ 818

Derivatives (Tables)

Derivatives (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Derivatives Outstanding Included in Other Assets and Liabilities	The following tables summarize the Company’s derivatives outstanding included in other assets and other liabilities in the accompanying Consolidated Balance Sheets: September 30, 2018 Derivative Assets Derivative Liabilities Notional Fair Value Notional Fair Value (Dollars in thousands) Derivatives designated as cash flow hedges: Interest rate contracts - pay fixed, receive floating $ 250,000 $ 1,750 $ — $ — Total cash flow hedges 250,000 1,750 — — Derivatives not designated as hedges: Interest rate contracts - pay floating, receive fixed 543,748 6,682 1,005,701 25,549 Interest rate contracts - pay fixed, receive floating 1,005,701 22,954 543,748 4,087 Interest rate caps purchased 94,534 312 — — Interest rate caps sold — — 94,534 312 Risk participation agreements — — 34,307 — Total derivatives not designated as hedges 1,643,983 29,948 1,678,290 29,948 Total derivatives $ 1,893,983 $ 31,698 $ 1,678,290 $ 29,948 December 31, 2017 Derivative Assets Derivative Liabilities Notional Fair Value Notional Fair Value (Dollars in thousands) Derivatives not designated as hedges: Interest rate contracts - pay floating, receive fixed $ 757,887 $ 11,678 $ 380,233 $ 4,180 Interest rate contracts - pay fixed, receive floating 380,233 — 757,887 7,498 Interest rate caps - purchased 94,884 155 — — Interest rate caps - sold — — 94,884 155 Total derivatives $ 1,233,004 $ 11,833 $ 1,233,004 $ 11,833
Derivative Instruments, Gain (Loss) [Table Text Block]	The following table presents the net gains (losses) recorded in accumulated other comprehensive income and the Consolidated Statements of Income relating to the cash flow derivative instruments for the nine months ended September 30, 2018 : September 30, 2018 Amount of Gain (Loss) Recognized in AOCI Amount of Gain (Loss) Reclassified from AOCI to Interest Expense Location of Gain (Loss) Reclassified from AOCI into Income (Dollars in thousands) Derivatives designated as cash flow hedges: Interest rate contracts - pay fixed, receive floating 1,313 — Interest on borrowings
Summary of Gross and Net Fair Values of Derivatives Outstanding Included in Other Liabilities	The following tables summarize the gross and net fair values of the Company’s derivatives outstanding with this counterparty included in other liabilities in the accompanying Consolidated Balance Sheets: September 30, 2018 Gross amounts of recognized liabilities Gross amounts offset in the consolidated balance sheets Net amounts in the consolidated balance sheets (Dollars in thousands) Offsetting derivative liabilities: Counterparty A - Interest rate contracts $ 24,648 $ (1,694 ) $ 22,954 Centrally Cleared - Interest rate contracts $ 901 $ (4,989 ) $ (4,088 ) December 31, 2017 Gross amounts of recognized liabilities Gross amounts offset in the consolidated balance sheets Net amounts in the consolidated balance sheets (Dollars in thousands) Offsetting derivative liabilities: Counterparty A - Interest rate contracts $ 11,833 $ (4,491 ) $ 7,342

Deposits (Tables)

Deposits (Tables)	9 Months Ended
	Sep. 30, 2018
Banking and Thrift [Abstract]
Summary of Company's Deposits by Category	The following table sets forth the Company’s deposits by category: September 30, 2018 December 31, 2017 (Dollars in thousands) Noninterest-bearing demand deposits $ 1,577,741 $ 1,236,685 Interest-bearing demand deposits 1,207,859 1,454,097 Interest-bearing NOW accounts 410,226 363,191 Savings and money market accounts 2,607,093 3,013,237 Time deposits 4,353,196 2,606,717 Total deposits $ 10,156,115 $ 8,673,927 Time deposits $100,000 and greater $ 3,005,138 $ 1,983,445 Time deposits greater than $250,000 1,623,796 1,078,702

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Schedule of Changes in Accumulated Other Comprehensive Income	Changes in AOCI for the periods indicated are summarized as follows: Three Months Ended September 30, 2018 2017 Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax (Dollars in thousands) Unrealized gains (losses) on debt securities available for sale: Balance at beginning of period $ (25,353 ) $ 6,326 $ (19,027 ) $ 25,468 $ (9,744 ) $ 15,724 Net unrealized holding gain (loss) arising during the period (11,095 ) 2,768 (8,327 ) (967 ) 369 (598 ) Amounts reclassified to (gain) loss on investment securities, net 1,677 (418 ) 1,259 (1,409 ) 540 (869 ) Balance at end of period (34,771 ) 8,676 (26,095 ) 23,092 (8,835 ) 14,257 Unrealized gains (losses) on derivative instruments: Balance at beginning of period 124 (31 ) 93 — — — Net unrealized holding gains (losses) arising during the period 1,626 (406 ) 1,220 — — — Balance at end of period 1,750 (437 ) 1,313 — — — Total accumulated other comprehensive income (loss) $ (33,021 ) $ 8,239 $ (24,782 ) $ 23,092 $ (8,835 ) $ 14,257 Nine Months Ended September 30, 2018 2017 Before Tax Net Before Tax Net (Dollars in thousands) Balance at beginning of period $ 14,402 $ (5,509 ) $ 8,893 $ (6,504 ) $ 2,509 $ (3,995 ) Unrealized gain (loss) on investment securities available for sale: Net unrealized holdings gain (loss) arising during the period (48,163 ) 12,017 (36,146 ) 31,650 (12,131 ) 19,519 Amounts reclassified to (gain) loss on investment securities 577 (144 ) 433 (2,054 ) 787 (1,267 ) Cumulative adjustment from adoption of new accounting standards (1,587 ) 2,312 725 — — — Balance at end of period (34,771 ) 8,676 (26,095 ) 23,092 (8,835 ) 14,257 Unrealized gains (losses) on derivative instruments: Balance at beginning of period — — — — — — Net unrealized holding gains (losses) arising during the period 1,750 (437 ) 1,313 — — — Balance at end of period 1,750 (437 ) 1,313 — — — Total accumulated other comprehensive income (loss) $ (33,021 ) $ 8,239 $ (24,782 ) $ 23,092 $ (8,835 ) $ 14,257

Basic and Diluted Earnings Pe_2

Basic and Diluted Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	The following table presents the computation of basic and diluted EPS: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (Dollars in thousands, except share and per share data) Net income available to common stockholders $ 43,480 $ 32,160 $ 126,313 $ 106,230 Weighted average number of common shares - basic 46,693,707 43,333,947 46,213,176 42,580,426 Effect of dilutive securities: Employee stock-based compensation awards 2,111,164 2,855,521 2,259,481 3,380,169 Weighted average number of common shares - diluted 48,804,871 46,189,468 48,472,657 45,960,595 Basic earnings per share $ 0.93 $ 0.74 $ 2.73 $ 2.49 Diluted earnings per share $ 0.89 $ 0.70 $ 2.61 $ 2.31 Weighted average number of anti-dilutive equity awards 48,708 41,040 25,332 20,942

Stock-Based Compensation and _2

Stock-Based Compensation and Other Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2018
Share-based Compensation Arrangements by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding	The following table presents the activity during the nine months ended September 30, 2018 related to restricted stock units from the 2016 Plan: 2016 Stock Incentive Plan Restricted Stock Awards Restricted Stock Unit Awards Performance Restricted Stock Unit Awards Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value Shares Weighted Average Grant Date Fair Value (Dollars in thousands, except per share data) Outstanding at January 1, 2018 96,133 $ 42.23 88,015 $ 50.34 73,144 $ 47.85 Granted — — 72,567 56.52 84,836 56.10 Vested — — (20,459 ) 52.38 — — Forfeited — — (5,300 ) 52.62 — — Outstanding at September 30, 2018 96,133 $ 42.23 134,823 $ 53.27 157,980 $ 52.28
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award	A summary of selected data related to stock-based compensation expense for the nine months ended September 30, 2018 and 2017 are as follows: Restricted Stock Awards Restricted Stock Unit Awards Performance Restricted Stock Unit Awards Nine Months Ended September 30, 2018 2017 2018 2017 2018 2017 (Dollars in thousands) Stock-based compensation expense $ 1,968 $ 2,570 $ 1,710 $ 863 $ 1,855 $ 649 Unrecognized compensation expense related to stock-based compensation $ 1,145 $ 4,216 $ 6,183 $ 1,067 $ 5,437 $ 2,851 Weighted-average life over which expense is expected to be recognized (years) 0.78 1.41 4.05 3.65 1.96 2.25
2009 Stock Option Plan
Schedule of Option Activity	Option grant activity for the period indicated is summarized as follows: 2009 Stock Option Plan Options Weighted Average Exercise Price Outstanding at January 1, 2018 1,314,924 $ 20.65 Granted — — Exercised (142,602 ) 21.15 Forfeited — — Expired — — Outstanding at September 30, 2018 1,172,322 $ 20.58 Exercisable at September 30, 2018 1,172,322 $ 20.58 Vested at September 30, 2018 1,172,322 $ 20.58 Vested and expected to vest at September 30, 2018 1,172,322 $ 20.58
2013 Stock Incentive Plan
Schedule of Option Activity	Option grant activity for the period indicated is summarized as follows: 2013 Stock Incentive Plan Options Options Weighted Average Exercise Price Outstanding at January 1, 2018 1,424,953 $ 20.79 Granted — — Exercised (245,611 ) 20.53 Forfeited — — Expired — — Outstanding at September 30, 2018 1,179,342 $ 20.84 Exercisable at September 30, 2018 1,179,342 $ 20.84 Vested at September 30, 2018 1,179,342 $ 20.84 Vested and expected to vest at September 30, 2018 1,179,342 $ 20.84
2016 Stock Incentive Plan
Schedule of Option Activity	Option grant activity for the period indicated is summarized as follows: 2016 Stock Incentive Plan Options Options Weighted Average Exercise Price Outstanding at January 1, 2018 762,500 $ 36.64 Granted — — Exercised — — Forfeited (30,000 ) 36.11 Expired — — Outstanding at September 30, 2018 732,500 $ 36.66 Exercisable at September 30, 2018 — $ — Vested at September 30, 2018 — $ — Vested and expected to vest at September 30, 2018 732,500 $ 36.66

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Summary of Unfunded Commitments	Unfunded commitments are as follows: September 30, 2018 December 31, 2017 (Dollars in thousands) Commitments to fund loans $ 1,159,541 $ 926,405 Unused lines of credit 774,695 571,587 Commercial and standby letters of credit 50,945 46,520 Total $ 1,985,181 $ 1,544,512

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables present the assets and liabilities measured at fair value on a recurring basis: September 30, 2018 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: U.S. Government agencies and sponsored enterprises obligations $ — $ 84,232 $ — $ 84,232 U.S. Government agencies and sponsored enterprises mortgage-backed securities — 604,158 — 604,158 State and municipal obligations — 22,882 — 22,882 Asset-backed securities — 778,322 — 778,322 Corporate bonds and other debt securities 52,966 733,143 — 786,109 Preferred stocks and other equity securities 12,590 58,425 — 71,015 Derivative assets — 31,699 — 31,699 Total $ 65,556 $ 2,312,861 $ — $ 2,378,417 Liabilities: Derivative liabilities $ — $ 29,949 $ — $ 29,949 Total $ — $ 29,949 $ — $ 29,949 December 31, 2017 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: U.S. Government agencies and sponsored enterprises obligations $ — $ 42,838 $ — $ 42,838 U.S. Government agencies and sponsored enterprises mortgage-backed securities — 595,237 — 595,237 State and municipal obligations — 26,172 — 26,172 Asset-backed securities — 610,546 — 610,546 Corporate bonds and other debt securities 55,970 699,933 — 755,903 Preferred stocks and other equity securities 12,954 77,153 — 90,107 Derivative assets — 11,833 — 11,833 Total $ 68,924 $ 2,063,712 $ — $ 2,132,636 Liabilities: Derivative liabilities $ — $ 11,833 $ — $ 11,833 Total $ — $ 11,833 $ — $ 11,833
Significant Unobservable Inputs in Fair Value Measurement Level 3 Assets and Liabilities	The following table shows significant unobservable inputs used in the non-recurring fair value measurement of level 3 assets and liabilities: Level 3 Assets: September 30, 2018 December 31, 2017 Valuation Technique Unobservable Inputs Range (Weighted Average) (Dollars in thousands) Impaired loans $ 28,969 $ 6,153 Third party appraisals and discounted cash flows Collateral discounts and discount rates 0% - 100% (7.1%) Other real estate owned 10,534 14,906 Third party appraisals Collateral discounts and estimated cost to sell 10 %
Fair Value, Assets Measured on Nonrecurring Basis	The following table provides information about certain assets measured at fair value on a non-recurring basis: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (Dollars in thousands) Negative valuation adjustments: Impaired loans $ 122 $ — $ 1,715 $ — Foreclosed real estate 9 54 1,106 437
Schedule of Carrying Amounts and Estimated Fair Values, as well as the Level within the Fair Value Hierarchy	The carrying amounts and estimated fair values, as well as the level within the fair value hierarchy, of the Company’s financial instruments are as follows: September 30, 2018 Carrying Value Fair Value Level 1 Level 2 Level 3 (Dollars in thousands) Financial Assets: Cash and cash equivalents $ 200,509 $ 200,509 $ 200,509 $ — $ — Available for sale debt securities 2,275,703 2,275,703 52,966 2,222,737 — Preferred stocks and other equity securities 71,015 71,015 12,590 58,425 — FHLB and other bank stock 65,847 65,847 — 65,847 — Loans, net 9,263,660 9,185,518 — — 9,185,518 Loans held for sale 980 980 — 980 — Bank-owned life insurance 215,421 215,421 — 215,421 — Derivative assets 31,699 31,699 — 31,699 — Financial Liabilities: Deposits $ 10,156,115 $ 10,133,649 $ — $ 10,133,649 $ — Advances from the FHLB and other borrowings 825,558 853,004 — 853,004 — Derivative liabilities 29,949 29,949 — 29,949 — December 31, 2017 Carrying Value Fair Value Level 1 Level 2 Level 3 (Dollars in thousands) Financial Assets: Cash and cash equivalents $ 115,921 $ 115,921 $ 115,921 $ — $ — Available for sale debt securities 2,030,696 2,130,696 55,970 1,974,726 — Preferred stocks and other equity securities 90,107 90,107 12,954 77,153 — FHLB and other bank stock 56,881 56,881 — 56,881 — Loans, net 7,930,639 7,877,094 — — 7,877,094 Loans held for sale 12,736 12,736 — 12,736 — Bank-owned life insurance 201,069 201,069 — 201,069 — Derivative assets 11,833 11,833 — 11,833 — Financial Liabilities: Deposits $ 8,673,927 $ 8,664,125 $ — $ 8,664,125 $ — Advances from the FHLB and other borrowings 749,113 740,941 — 740,941 — Derivative liabilities 11,833 11,833 — 11,833 —

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]	The following table presents noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606, for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (Dollars in thousands) Noninterest Income In-scope of Topic 606: NSF/OD Fees $ 416 $ 328 $ 1,149 $ 1,113 Fees on deposit accounts 850 613 2,354 1,645 Service charges and fees 1,266 941 3,503 2,758 ATM and debit card income 261 551 1,571 1,762 Safe deposit box 19 18 70 67 Merchant revenue 214 188 633 531 Ancillary fees and income 195 88 457 266 CD custody income and fees 161 — 384 — Misc other income 100 134 581 3,922 Gain (loss) on sales of other real estate owned (70 ) (143 ) 43 (121 ) Noninterest Income (in-scope of Topic 606) $ 2,146 $ 1,777 $ 7,242 $ 9,185 Out-of-scope of Topic 606: Gain (loss) on sale of loans $ 142 $ 1,233 $ 92 $ 2,199 Gain (loss) on sale of fixed assets (24 ) 6 (13 ) 7 Loan and other fees 5,043 2,831 13,261 8,374 Bank-owned life insurance income 1,439 1,422 4,228 4,250 Income from resolution of acquired assets 202 466 603 1,548 Gain (loss) on investment securities (184 ) 690 (1,472 ) 1,722 Noninterest Income (out-of-scope of Topic 606) 6,618 6,648 16,699 18,100 Total noninterest income $ 8,764 $ 8,425 $ 23,941 $ 27,285

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)Banking_Center	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Number of banking centers | Banking_Center			51
Stranded tax effect					$ 1,700
Excess tax benefit	$ 168	$ 2,100	$ 2,900	$ 18,000
Retained Earnings
Cumulative adjustment from adoption of new accounting standards (1)					(725)
ASU 2016-01
Equity securities, unrealized gain	$ 1,100		$ (1,100)		1,600
ASU 2016-01 | Retained Earnings
Cumulative adjustment from adoption of new accounting standards (1)					$ 1,000

Business Acquisitions (Details)

Business Acquisitions (Details) - USD ($) $ in Thousands	Mar. 01, 2018	Sep. 30, 2018	Jul. 24, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill		$ 139,529		$ 81,204
Synovus Financial Corp.
Business Acquisition [Line Items]
Conversion ratio for sale of business (in shares)			1.055
Floridian
Business Acquisition [Line Items]
Interest acquired, percentage	100.00%
Number of FCB shares issued per Floridian share (in shares)	0.4584
Number of FCB shares issued in Floridian acquisition (in shares)	1,754,362
Cash paid for Floridian fractional shares	$ 7
Liability incurred related to settlement of outstanding stock options	5,198	5,198
Floridian assets acquired	507,693	506,835
Floridian liabilities assumed	466,953	465,840
Goodwill	$ 58,580	58,325
Decrease in assets acquired		(858)
Decrease in liabilities acquired		(1,113)
Goodwill resulting from acquisition		$ (255)

Business Acquisitions - Schedul

Business Acquisitions - Schedule of Purchase Price Allocation (Details) - USD ($) $ in Thousands	Mar. 01, 2018	Sep. 30, 2018	Dec. 31, 2017
Fair value of liabilities assumed:
Goodwill		$ 139,529	$ 81,204
Floridian
Business Acquisition [Line Items]
Common stock issued	$ 94,122	94,122
Liability incurred related to settlement of outstanding stock options	5,198	5,198
Total consideration transferred	99,320	99,320
Fair value of assets acquired:
Cash and cash equivalents	16,699	16,656
Adjustment, cash and cash equivalents		(43)
Investment securities	38,772	38,772
Loans	425,894	425,894
Other real estate owned	113	111
Adjustment, real estate		(2)
Core deposit intangible	4,580	4,580
Fixed assets	3,425	3,425
Deferred tax asset, net	5,043	4,804
Adjustment, deferred tax asset		(239)
Bank-owned life insurance	10,489	10,489
Other assets	2,678	2,104
Other assets		(574)
Total identifiable assets acquired	507,693	506,835
Decrease in assets acquired		(858)
Fair value of liabilities assumed:
Deposits	382,333	382,333
FHLB advances and other borrowings	73,389	73,389
Other liabilities	11,231	10,118
Adjustment, other liabilities		(1,113)
Total liabilities assumed	466,953	465,840
Decrease in liabilities acquired		(1,113)
Fair value of net assets acquired	40,740	40,995
Adjustment, net		255
Goodwill	$ 58,580	58,325
Goodwill resulting from acquisition		$ (255)

Investment Securities - Additio

Investment Securities - Additional Information (Detail) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018USD ($)security	Sep. 30, 2018USD ($)security	Dec. 31, 2017USD ($)
Carrying value of pledged securities | $	$ 950.4	$ 950.4	$ 834.9
Number of securities in security portfolio	355	355
Securities in an unrealized loss position	245	245
Securities in an unrealized loss position for less than 12 months	137	137
ASU 2016-01
Equity securities, unrealized gain | $	$ 1.1	$ (1.1)	$ 1.6

Investment Securities - Summary

Investment Securities - Summary of Amortized Cost, Gross Unrealized Gains and Losses and Approximate Fair Values of Securities Available for Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Amortized Cost	$ 2,310,474	$ 2,017,881
Available for sale securities, Unrealized Gains	8,014	22,407
Available for sale securities, Unrealized Losses	42,785	9,592
Available for sale securities, Fair Value	2,275,703	2,030,696
U.S. Government agencies and sponsored enterprises obligations
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Amortized Cost	86,941	43,471
Available for sale securities, Unrealized Gains	0	38
Available for sale securities, Unrealized Losses	2,709	671
Available for sale securities, Fair Value	84,232	42,838
U.S. Government agencies and sponsored enterprises mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Amortized Cost	627,668	600,310
Available for sale securities, Unrealized Gains	9	1,716
Available for sale securities, Unrealized Losses	23,519	6,789
Available for sale securities, Fair Value	604,158	595,237
State and municipal obligations
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Amortized Cost	24,485	26,766
Available for sale securities, Unrealized Gains	66	125
Available for sale securities, Unrealized Losses	1,669	719
Available for sale securities, Fair Value	22,882	26,172
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Amortized Cost	780,250	608,340
Available for sale securities, Unrealized Gains	330	2,306
Available for sale securities, Unrealized Losses	2,258	100
Available for sale securities, Fair Value	778,322	610,546
Corporate bonds and other debt securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities, Amortized Cost	791,130	738,994
Available for sale securities, Unrealized Gains	7,609	18,222
Available for sale securities, Unrealized Losses	12,630	1,313
Available for sale securities, Fair Value	$ 786,109	$ 755,903

Investment Securities - Schedul

Investment Securities - Schedule of Amortized Cost and Estimated Fair Value of Securities Available for Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Available for sale, Due in one year or less at Amortized Cost	$ 57,430
Available for sale, Due after one year through five years at Amortized Cost	290,655
Available for sale, Due after five years through ten years at Amortized Cost	138,696
Available for sale, Due after ten years at Amortized Cost	328,834
U.S. Government agencies and sponsored enterprises obligations, mortgage-backed securities and asset-backed securities at Amortized Cost	1,494,859
Available for sale securities, Amortized Cost	2,310,474	$ 2,017,881
Available for sale securities, Due in one year or less at Fair Value	57,475
Available for sale securities, Due after one year through five years at Fair Value	287,076
Available for sale securities, Due after five years through ten years at Fair Value	135,574
Available for sale securities, Due after ten years at Fair Value	328,866
U.S. Government agencies and sponsored enterprises obligations, mortgage-backed securities and asset-backed securities at Fair Value	1,466,712
Total available for sale, Fair Value	$ 2,275,703	$ 2,030,696

Investment Securities - Summa_2

Investment Securities - Summary of Estimated Fair Values and Gross Unrealized Losses on Investment Securities Available for Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities at Fair Value, Less than 12 months	$ 1,070,692	$ 462,039
Available for sale securities Unrealized Loss, Less than 12 Months	19,716	3,446
Available for sale securities at Fair Value, 12 months or more	453,045	217,622
Available for sale securities Unrealized Loss, 12 months or more	23,069	6,146
Available for sale securities, Total Fair Value	1,523,737	679,661
Available for sale securities, Total Unrealized Loss	42,785	9,592
U.S. Government agencies and sponsored enterprises obligations
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities at Fair Value, Less than 12 months	51,529	31,518
Available for sale securities Unrealized Loss, Less than 12 Months	906	268
Available for sale securities at Fair Value, 12 months or more	32,703	7,157
Available for sale securities Unrealized Loss, 12 months or more	1,803	403
Available for sale securities, Total Fair Value	84,232	38,675
Available for sale securities, Total Unrealized Loss	2,709	671
U.S. Government agencies and sponsored enterprises mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities at Fair Value, Less than 12 months	279,436	207,735
Available for sale securities Unrealized Loss, Less than 12 Months	8,128	1,836
Available for sale securities at Fair Value, 12 months or more	300,994	175,810
Available for sale securities Unrealized Loss, 12 months or more	15,391	4,953
Available for sale securities, Total Fair Value	580,430	383,545
Available for sale securities, Total Unrealized Loss	23,519	6,789
State and municipal obligations
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities at Fair Value, Less than 12 months	0	192
Available for sale securities Unrealized Loss, Less than 12 Months	0	2
Available for sale securities at Fair Value, 12 months or more	20,772	23,813
Available for sale securities Unrealized Loss, 12 months or more	1,669	717
Available for sale securities, Total Fair Value	20,772	24,005
Available for sale securities, Total Unrealized Loss	1,669	719
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities at Fair Value, Less than 12 months	348,117	36,542
Available for sale securities Unrealized Loss, Less than 12 Months	2,196	100
Available for sale securities at Fair Value, 12 months or more	7,002	0
Available for sale securities Unrealized Loss, 12 months or more	62	0
Available for sale securities, Total Fair Value	355,119	36,542
Available for sale securities, Total Unrealized Loss	2,258	100
Corporate bonds and other debt securities
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities at Fair Value, Less than 12 months	391,610	186,052
Available for sale securities Unrealized Loss, Less than 12 Months	8,486	1,240
Available for sale securities at Fair Value, 12 months or more	91,574	10,842
Available for sale securities Unrealized Loss, 12 months or more	4,144	73
Available for sale securities, Total Fair Value	483,184	196,894
Available for sale securities, Total Unrealized Loss	$ 12,630	$ 1,313

Investment Securities - Summa_3

Investment Securities - Summary of Gross Realized Gains and Losses on Sale of Securities Available for Sale (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 2	$ 1,251	$ 147	$ 1,945
Gross realized losses	(1,248)	(1,533)	(1,254)	(2,739)
Net realized gains (losses)	$ (1,246)	$ (282)	$ (1,107)	$ (794)

Loans, Net - Schedule of Loans

Loans, Net - Schedule of Loans by Portfolio and Segment (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 9,316,808		$ 7,977,784
Allowance for loan losses	(53,148)	$ (50,570)	(47,145)	$ (44,291)	$ (41,334)	$ (37,897)
Loans, net	9,263,660		7,930,639
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	687,406		316,399
Allowance for loan losses	(1,167)			(1,187)
New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	8,629,402		7,661,385
Allowance for loan losses	(50,115)			(39,416)
Net deferred fees, costs, and premium and discount	(9,200)		(6,600)
Total real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	7,329,432		6,318,053
Total real estate loans | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	6,723,381		6,021,029
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,766,890		2,245,859
Allowance for loan losses	(16,154)	(15,381)	(13,870)	(13,084)	(12,155)	(10,123)
Commercial real estate | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	(188)			(331)
Commercial real estate | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,528,748		2,103,788
Allowance for loan losses	(14,410)			(11,089)
Owner-occupied commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,216,201		1,003,881
Allowance for loan losses	(3,811)	(3,946)	(3,365)	(3,627)	(3,286)	(2,597)
Owner-occupied commercial real estate | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	(51)			(64)
Owner-occupied commercial real estate | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,134,793		987,781
Allowance for loan losses	(3,760)			(3,563)
1-4 single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,426,038		2,270,570
Allowance for loan losses	(6,958)	(7,310)	(7,978)	(8,386)	(8,749)	(7,379)
1-4 single family residential | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	(144)			(214)
1-4 single family residential | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,245,139		2,185,362
Allowance for loan losses	(6,806)			(8,147)
Construction, land and development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	820,443		703,518
Allowance for loan losses	(5,354)	(4,076)	(4,345)	(4,560)	(4,713)	(4,677)
Construction, land and development | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	(130)			(36)
Construction, land and development | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	754,972		684,462
Allowance for loan losses	(5,121)			(4,377)
Home equity loans and lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	99,860		94,225
Allowance for loan losses	(682)	(704)	(674)	(696)	(884)	(648)
Home equity loans and lines of credit | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	(204)			(224)
Home equity loans and lines of credit | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	59,729		59,636
Allowance for loan losses	(478)			(472)
Total other loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,987,376		1,659,731
Total other loans | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,906,021		1,640,356
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	19,185		7,666
Allowance for loan losses	(191)	(219)	(272)	(232)	(251)	(228)
Consumer | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	(3)			(7)
Consumer | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,976		5,984
Allowance for loan losses	(69)			(73)
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,968,191		1,652,065
Allowance for loan losses	(19,998)	$ (18,934)	(15,141)	(12,206)	$ (11,296)	$ (12,245)
Commercial and industrial | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	(447)			(311)
Commercial and industrial | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,902,045		1,634,372
Allowance for loan losses	(19,471)			(11,695)
ASC 310-30 Loans | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	215,370		159,069
Allowance for loan losses	(1,866)			(2,188)
ASC 310-30 Loans | Total real estate loans | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	194,608		145,015
Allowance for loan losses	(1,667)		(1,618)
ASC 310-30 Loans | Total real estate loans | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Commercial real estate | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	133,778		104,335
Allowance for loan losses	(1,556)		(1,448)	(1,664)
ASC 310-30 Loans | Commercial real estate | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Owner-occupied commercial real estate | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0	0
ASC 310-30 Loans | Owner-occupied commercial real estate | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | 1-4 single family residential | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	32,240		27,513
Allowance for loan losses	(8)		(25)	(25)
ASC 310-30 Loans | 1-4 single family residential | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Construction, land and development | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	28,590		13,167
Allowance for loan losses	(103)		(145)	(147)
ASC 310-30 Loans | Construction, land and development | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Home equity loans and lines of credit | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0	0
ASC 310-30 Loans | Home equity loans and lines of credit | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Total other loans | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	20,762		14,054
Allowance for loan losses	(199)		(271)
ASC 310-30 Loans | Total other loans | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Consumer | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,259		1,423
Allowance for loan losses	(119)		(145)	(152)
ASC 310-30 Loans | Consumer | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Commercial and industrial | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	19,503		12,631
Allowance for loan losses	(80)		(126)	$ (200)
ASC 310-30 Loans | Commercial and industrial | New Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Allowance for loan losses	0		0
Non-ASC 310-30 Loans | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	472,036		157,330
Non-ASC 310-30 Loans | Total real estate loans | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	411,443		152,009
Non-ASC 310-30 Loans | Commercial real estate | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	104,364		37,736
Non-ASC 310-30 Loans | Owner-occupied commercial real estate | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	81,408		16,100
Non-ASC 310-30 Loans | 1-4 single family residential | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	148,659		57,695
Non-ASC 310-30 Loans | Construction, land and development | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	36,881		5,889
Non-ASC 310-30 Loans | Home equity loans and lines of credit | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	40,131		34,589
Non-ASC 310-30 Loans | Total other loans | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	60,593		5,321
Non-ASC 310-30 Loans | Consumer | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	13,950		259
Non-ASC 310-30 Loans | Commercial and industrial | Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 46,643		$ 5,062

Loans, Net - Additional Informa

Loans, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Pledged loans as collateral for FHLB advances, carrying amount	$ 3,440,000		$ 3,440,000		$ 3,360,000
Loans	9,316,808		9,316,808		7,977,784
Purchase of loans from third parties			7,400	$ 2,800
Sale of loans to third parties	6,200	$ 73,400	26,000	232,300
Reclassification between non-accretable and accretable discount			3,417	$ (2,700)
ASC 310-30 Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principle balance of ASC 310-30 loans	274,300		274,300		183,900
1-4 single family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investments of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are in process	4,200		4,200
Syndicated National Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 288,500		$ 288,500		$ 289,100

Loans, Net - Summary of Changes

Loans, Net - Summary of Changes in Accretable Discount for ASC 310-30 Loans (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning Balance	$ 41,162	$ 60,990
Additions to accretable discount from FLCB acquisition	14,393	0
Accretion	(10,857)	(13,965)
Reclassifications from (to) non-accretable difference	3,417	(2,747)
Ending Balance	$ 48,115	$ 44,278

Allowance for Loan Losses - Sum

Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses by Loan Class and Portfolio Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 50,570	$ 41,334	$ 47,145	$ 37,897	$ 37,897
Total provision	(2,220)	(2,871)	(5,801)	(6,629)
Total charge-offs	(145)	(45)	(360)	(509)
Total recoveries	502	131	561	274
Ending balance	53,148	44,291	53,148	44,291	47,145
Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	(156)	304	(168)	177
Total charge-offs	(118)	(42)	(154)	(109)
Total recoveries	23	34	23	63
Ending balance	1,167	1,187	1,167	1,187
Acquired Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	212	125	337	851
Total charge-offs	(27)	0	(206)	(116)
Total recoveries	470	97	518	211
Ending balance	1,866	2,188	1,866	2,188
New Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	(2,276)	(1,800)	(7,470)	(6,157)
Total charge-offs	0	(3)	0	(284)
Total recoveries	9	0	20	0
Ending balance	50,115	39,416	50,115	39,416
Unallocated Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	0	(1,500)	1,500	(1,500)	(1,500)
Ending balance	0	1,500	0	1,500
Unallocated Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	0		0
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	15,381	12,155	13,870	10,123	10,123
Total provision	(526)	(932)	(2,181)	(3,090)
Total charge-offs	(119)	(30)	(274)	(170)
Total recoveries	366	27	377	41
Ending balance	16,154	13,084	16,154	13,084	13,870
Commercial real estate | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	8	(30)	32	15
Total charge-offs	(118)	(30)	(118)	(30)
Total recoveries	0	0	0	0
Ending balance	188	331	188	331
Commercial real estate | Acquired Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			1,448
Total provision	26	41	102	623
Total charge-offs	(1)	0	(156)	(9)
Total recoveries	366	27	366	41
Ending balance	1,556	1,664	1,556	1,664	1,448
Commercial real estate | New Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	(560)	(943)	(2,315)	(3,728)
Total charge-offs	0	0	0	(131)
Total recoveries	0	0	11	0
Ending balance	14,410	11,089	14,410	11,089
Commercial real estate | New Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			0
Ending balance	0		0		0
Commercial real estate | Unallocated Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	0	0	0	0
Ending balance	0	0	0	0
Owner-occupied commercial real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	3,946	3,286	3,365	2,597	2,597
Total provision	147	(341)	(434)	(1,030)
Total charge-offs	0	0	0	0
Total recoveries	12	0	12	0
Ending balance	3,811	3,627	3,811	3,627	3,365
Owner-occupied commercial real estate | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	3	1	4	(3)
Total charge-offs	0	0	0	0
Total recoveries	0	0	0	0
Ending balance	51	64	51	64
Owner-occupied commercial real estate | Acquired Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			0
Total provision	3	0	3	0
Total charge-offs	0	0	0	0
Total recoveries	3	0	3	0
Ending balance	0	0	0	0	0
Owner-occupied commercial real estate | New Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	141	(342)	(441)	(1,027)
Total charge-offs	0	0	0	0
Total recoveries	9	0	9	0
Ending balance	3,760	3,563	3,760	3,563
Owner-occupied commercial real estate | New Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			0
Ending balance	0		0		0
Owner-occupied commercial real estate | Unallocated Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	0	0	0	0
Ending balance	0	0	0	0
1-4 single family residential
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	7,310	8,749	7,978	7,379	7,379
Total provision	354	384	1,040	(1,081)
Total charge-offs	(22)	(9)	(22)	(104)
Total recoveries	24	30	42	30
Ending balance	6,958	8,386	6,958	8,386	7,978
1-4 single family residential | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	35	49	62	48
Total charge-offs	0	(9)	0	(69)
Total recoveries	23	30	23	30
Ending balance	144	214	144	214
1-4 single family residential | Acquired Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			25
Total provision	(14)	0	15	(31)
Total charge-offs	(22)	0	(22)	(35)
Total recoveries	1	0	19	0
Ending balance	8	25	8	25	25
1-4 single family residential | New Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	333	335	963	(1,098)
Total charge-offs	0	0	0	0
Total recoveries	0	0	0	0
Ending balance	6,806	8,147	6,806	8,147
1-4 single family residential | New Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			0
Ending balance	0		0		0
1-4 single family residential | Unallocated Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	0	0	0	0
Ending balance	0	0	0	0
Construction, land and development
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	4,076	4,713	4,345	4,677	4,677
Total provision	(1,184)	153	(902)	74
Total charge-offs	0	0	0	(43)
Total recoveries	93	0	106	0
Ending balance	5,354	4,560	5,354	4,560	4,345
Construction, land and development | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	(71)	2	(94)	11
Total charge-offs	0	0	0	0
Total recoveries	0	0	0	0
Ending balance	130	36	130	36
Construction, land and development | Acquired Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			145
Total provision	115	38	149	49
Total charge-offs	0	0	0	(43)
Total recoveries	93	0	106	0
Ending balance	103	147	103	147	145
Construction, land and development | New Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	(1,228)	113	(957)	14
Total charge-offs	0	0	0	0
Total recoveries	0	0	0	0
Ending balance	5,121	4,377	5,121	4,377
Construction, land and development | New Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			0
Ending balance	0		0		0
Construction, land and development | Unallocated Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	0	0	0	0
Ending balance	0	0	0	0
Home equity loans and lines of credit
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	704	884	674	648	648
Total provision	22	185	(8)	(58)
Total charge-offs	0	(3)	0	(10)
Total recoveries	0	0	0	0
Ending balance	682	696	682	696	674
Home equity loans and lines of credit | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	(2)	227	(5)	12
Total charge-offs	0	0	0	(7)
Total recoveries	0	0	0	0
Ending balance	204	224	204	224
Home equity loans and lines of credit | Acquired Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			0
Total provision	0	0	0	0
Total charge-offs	0	0	0	0
Total recoveries	0	0	0	0
Ending balance	0	0	0	0	0
Home equity loans and lines of credit | New Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	24	(42)	(3)	(70)
Total charge-offs	0	(3)	0	(3)
Total recoveries	0	0	0	0
Ending balance	478	472	478	472
Home equity loans and lines of credit | New Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			0
Ending balance	0		0		0
Home equity loans and lines of credit | Unallocated Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	0	0	0	0
Ending balance	0	0	0	0
Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	18,934	11,296	15,141	12,245	12,245
Total provision	(1,057)	(839)	(4,886)	(69)
Total charge-offs	0	(3)	(53)	(182)
Total recoveries	7	74	24	74
Ending balance	19,998	12,206	19,998	12,206	15,141
Commercial and industrial | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	(129)	56	(170)	66
Total charge-offs	0	(3)	(36)	(3)
Total recoveries	0	4	0	4
Ending balance	447	311	447	311
Commercial and industrial | Acquired Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			126
Total provision	66	38	53	118
Total charge-offs	0	0	(17)	(29)
Total recoveries	7	70	24	70
Ending balance	80	200	80	200	126
Commercial and industrial | New Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	(994)	(933)	(4,769)	(253)
Total charge-offs	0	0	0	(150)
Total recoveries	0	0	0	0
Ending balance	19,471	11,695	19,471	11,695
Commercial and industrial | New Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			0
Ending balance	0		0		0
Commercial and industrial | Unallocated Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	0	0	0	0
Ending balance	0	0	0	0
Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	219	251	272	228	228
Total provision	24	19	70	125
Total charge-offs	(4)	0	(11)	0
Total recoveries	0	0	0	129
Ending balance	191	232	191	232	272
Consumer | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	0	(1)	3	28
Total charge-offs	0	0	0	0
Total recoveries	0	0	0	29
Ending balance	3	7	3	7
Consumer | Acquired Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			145
Total provision	16	8	15	92
Total charge-offs	(4)	0	(11)	0
Total recoveries	0	0	0	100
Ending balance	119	152	119	152	145
Consumer | New Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	8	12	52	5
Total charge-offs	0	0	0	0
Total recoveries	0	0	0	0
Ending balance	69	73	69	73
Consumer | New Loans | ASC 310-30 Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			0
Ending balance	0		0		$ 0
Consumer | Unallocated Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Total provision	0	0	0	0
Ending balance	$ 0	$ 0	$ 0	$ 0

Allowance for Loan Losses - Agi

Allowance for Loan Losses - Aging Analysis of Recorded Investment for Loans by Portfolio and Segment (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	$ 10,887	$ 14,246
Non- Accrual	7,338	3,293
Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	12,037	10,647
Non- Accrual	11,137	7,832
30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	2,229	7,326
30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	780	2,771
60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	1,320	3,627
60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	120	44
90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Total real estate loans | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	10,344	7,099
Non- Accrual	7,183	3,293
Total real estate loans | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	9,133	10,152
Non- Accrual	8,321	7,438
Total real estate loans | 30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	1,993	2,346
Total real estate loans | 30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	716	2,670
Total real estate loans | 60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	1,168	1,460
Total real estate loans | 60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	96	44
Total real estate loans | 90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Total real estate loans | 90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Commercial real estate | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	467	324
Non- Accrual	460	0
Commercial real estate | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	3,615	4,253
Non- Accrual	3,615	3,893
Commercial real estate | 30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	324
Commercial real estate | 30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	360
Commercial real estate | 60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	7	0
Commercial real estate | 60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Commercial real estate | 90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Commercial real estate | 90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Owner-occupied commercial real estate | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	3,267	993
Non- Accrual	2,440	0
Owner-occupied commercial real estate | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	486	784
Non- Accrual	486	494
Owner-occupied commercial real estate | 30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	843
Owner-occupied commercial real estate | 30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	290
Owner-occupied commercial real estate | 60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	827	150
Owner-occupied commercial real estate | 60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Owner-occupied commercial real estate | 90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Owner-occupied commercial real estate | 90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
1-4 single family residential | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	6,484	5,656
Non- Accrual	4,157	3,167
1-4 single family residential | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	1,773	2,267
Non- Accrual	1,677	1,331
1-4 single family residential | 30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	1,993	1,179
1-4 single family residential | 30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	892
1-4 single family residential | 60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	334	1,310
1-4 single family residential | 60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	96	44
1-4 single family residential | 90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
1-4 single family residential | 90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Construction, land and development | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Non- Accrual	0	0
Construction, land and development | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Non- Accrual	0	0
Construction, land and development | 30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Construction, land and development | 30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Construction, land and development | 60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Construction, land and development | 60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Construction, land and development | 90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Construction, land and development | 90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Home equity loans and lines of credit | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	126	126
Non- Accrual	126	126
Home equity loans and lines of credit | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	3,259	2,848
Non- Accrual	2,543	1,720
Home equity loans and lines of credit | 30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Home equity loans and lines of credit | 30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	716	1,128
Home equity loans and lines of credit | 60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Home equity loans and lines of credit | 60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Home equity loans and lines of credit | 90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Home equity loans and lines of credit | 90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Total other loans | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	543	7,147
Non- Accrual	155	0
Total other loans | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	2,904	495
Non- Accrual	2,816	394
Total other loans | 30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	236	4,980
Total other loans | 30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	64	101
Total other loans | 60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	152	2,167
Total other loans | 60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	24	0
Total other loans | 90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Total other loans | 90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Consumer | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	24	0
Non- Accrual	0	0
Consumer | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Non- Accrual	0	0
Consumer | 30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	24	0
Consumer | 30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Consumer | 60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Consumer | 60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Consumer | 90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Consumer | 90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Commercial and industrial | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	519	7,147
Non- Accrual	155	0
Commercial and industrial | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	2,904	495
Non- Accrual	2,816	394
Commercial and industrial | 30 to 59 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	212	4,980
Commercial and industrial | 30 to 59 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	64	101
Commercial and industrial | 60 to 89 Days Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	152	2,167
Commercial and industrial | 60 to 89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	24	0
Commercial and industrial | 90 Days or More Past Due | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	0	0
Commercial and industrial | 90 Days or More Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables past due	$ 0	$ 0

Allowance for Loan Losses - S_2

Allowance for Loan Losses - Summary of Commercial Non-ASC 310-30 and New Loans by Key Indicators of Credit Quality (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 9,316,808	$ 7,977,784
New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	8,629,402	7,661,385
Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	687,406	316,399
Pass | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	6,271,227	5,385,265
Pass | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	260,576	59,316
Special Mention | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	31,900	22,976
Special Mention | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	1,024	0
Substandard | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	17,431	2,162
Substandard | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	7,696	5,471
Doubtful | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	2,766,890	2,245,859
Commercial real estate | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	2,528,748	2,103,788
Commercial real estate | Pass | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	2,515,933	2,095,560
Commercial real estate | Pass | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	100,413	33,496
Commercial real estate | Special Mention | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	9,325	6,066
Commercial real estate | Special Mention | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial real estate | Substandard | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	3,490	2,162
Commercial real estate | Substandard | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	3,951	4,240
Commercial real estate | Doubtful | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial real estate | Doubtful | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Owner-occupied commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	1,216,201	1,003,881
Owner-occupied commercial real estate | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	1,134,793	987,781
Owner-occupied commercial real estate | Pass | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	1,131,769	987,781
Owner-occupied commercial real estate | Pass | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	80,835	15,607
Owner-occupied commercial real estate | Special Mention | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	584	0
Owner-occupied commercial real estate | Special Mention | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Owner-occupied commercial real estate | Substandard | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	2,440	0
Owner-occupied commercial real estate | Substandard | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	573	493
Owner-occupied commercial real estate | Doubtful | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Owner-occupied commercial real estate | Doubtful | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Construction, land and development
Financing Receivable, Recorded Investment [Line Items]
Loans	820,443	703,518
Construction, land and development | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	754,972	684,462
Construction, land and development | Pass | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	754,972	684,462
Construction, land and development | Pass | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	36,881	5,889
Construction, land and development | Special Mention | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Construction, land and development | Special Mention | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Construction, land and development | Substandard | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Construction, land and development | Substandard | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Construction, land and development | Doubtful | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Construction, land and development | Doubtful | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	1,968,191	1,652,065
Commercial and industrial | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	1,902,045	1,634,372
Commercial and industrial | Pass | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	1,868,553	1,617,462
Commercial and industrial | Pass | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	42,447	4,324
Commercial and industrial | Special Mention | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	21,991	16,910
Commercial and industrial | Special Mention | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	1,024	0
Commercial and industrial | Substandard | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	11,501	0
Commercial and industrial | Substandard | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	3,172	738
Commercial and industrial | Doubtful | New Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial and industrial | Doubtful | Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 0	$ 0

Allowance for Loan Losses - S_3

Allowance for Loan Losses - Summary of Loans Based on Method for Determining Allowance (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	$ 9,316,808		$ 7,977,784
Allowance for loan losses	53,148	$ 50,570	47,145	$ 44,291	$ 41,334	$ 37,897
New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	8,629,402		7,661,385
Allowance for loan losses	50,115			39,416
Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	687,406		316,399
Allowance for loan losses	1,167			1,187
Unallocated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	0
Loans - Recorded investment, Collectively evaluated for impairment	9,316,808		7,977,784
Allowance for credit loss, Individually evaluated for impairment	0
Allowance for credit loss, Collectively evaluated for impairment	0		1,500
Allowance for loan losses	0			1,500
Total real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	7,329,432		6,318,053
Total real estate loans | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	4,662		1,226
Loans - Recorded investment, Collectively evaluated for impairment	6,718,719		6,019,803
Loans - Recorded investment, ASC 310-30 loans	6,723,381		6,021,029
Allowance for credit loss, Individually evaluated for impairment	63		66
Allowance for credit loss, Collectively evaluated for impairment	30,512		27,736
Total real estate loans | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	4,157		4,655
Loans - Recorded investment, Collectively evaluated for impairment	407,286		147,354
Allowance for credit loss, Individually evaluated for impairment	0		129
Allowance for credit loss, Collectively evaluated for impairment	717		683
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	2,766,890		2,245,859
Allowance for loan losses	16,154	15,381	13,870	13,084	12,155	10,123
Commercial real estate | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	0		0
Loans - Recorded investment, Collectively evaluated for impairment	2,528,748		2,103,788
Loans - Recorded investment, ASC 310-30 loans	2,528,748		2,103,788
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	14,410		12,084
Allowance for loan losses	14,410			11,089
Commercial real estate | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	3,396		3,893
Loans - Recorded investment, Collectively evaluated for impairment	100,968		33,843
Allowance for credit loss, Individually evaluated for impairment	0		129
Allowance for credit loss, Collectively evaluated for impairment	188		209
Allowance for loan losses	188			331
Commercial real estate | Unallocated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for loan losses	0			0
Owner-occupied commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	1,216,201		1,003,881
Allowance for loan losses	3,811	3,946	3,365	3,627	3,286	2,597
Owner-occupied commercial real estate | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	2,899		0
Loans - Recorded investment, Collectively evaluated for impairment	1,131,894		987,781
Loans - Recorded investment, ASC 310-30 loans	1,134,793		987,781
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	3,760		3,310
Allowance for loan losses	3,760			3,563
Owner-occupied commercial real estate | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	0		0
Loans - Recorded investment, Collectively evaluated for impairment	81,408		16,100
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	51		55
Allowance for loan losses	51			64
Owner-occupied commercial real estate | Unallocated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for loan losses	0			0
1-4 single family residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	2,426,038		2,270,570
Allowance for loan losses	6,958	7,310	7,978	8,386	8,749	7,379
1-4 single family residential | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	1,637		1,096
Loans - Recorded investment, Collectively evaluated for impairment	2,243,502		2,184,266
Loans - Recorded investment, ASC 310-30 loans	2,245,139		2,185,362
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	6,806		7,769
Allowance for loan losses	6,806			8,147
1-4 single family residential | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	267		267
Loans - Recorded investment, Collectively evaluated for impairment	148,392		57,428
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	144		184
Allowance for loan losses	144			214
1-4 single family residential | Unallocated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for loan losses	0			0
Construction, land and development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	820,443		703,518
Allowance for loan losses	5,354	4,076	4,345	4,560	4,713	4,677
Construction, land and development | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	0		0
Loans - Recorded investment, Collectively evaluated for impairment	754,972		684,462
Loans - Recorded investment, ASC 310-30 loans	754,972		684,462
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	5,121		4,164
Allowance for loan losses	5,121			4,377
Construction, land and development | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	0		0
Loans - Recorded investment, Collectively evaluated for impairment	36,881		5,889
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	130		36
Allowance for loan losses	130			36
Construction, land and development | Unallocated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for loan losses	0			0
Home equity loans and lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	99,860		94,225
Allowance for loan losses	682	704	674	696	884	648
Home equity loans and lines of credit | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	126		130
Loans - Recorded investment, Collectively evaluated for impairment	59,603		59,506
Loans - Recorded investment, ASC 310-30 loans	59,729		59,636
Allowance for credit loss, Individually evaluated for impairment	63		66
Allowance for credit loss, Collectively evaluated for impairment	415		409
Allowance for loan losses	478			472
Home equity loans and lines of credit | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	494		495
Loans - Recorded investment, Collectively evaluated for impairment	39,637		34,094
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	204		199
Allowance for loan losses	204			224
Home equity loans and lines of credit | Unallocated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for loan losses	0			0
Total other loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	1,987,376		1,659,731
Total other loans | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	16,708		0
Loans - Recorded investment, Collectively evaluated for impairment	1,889,313		1,640,356
Loans - Recorded investment, ASC 310-30 loans	1,906,021		1,640,356
Allowance for credit loss, Individually evaluated for impairment	1,593		0
Allowance for credit loss, Collectively evaluated for impairment	17,947		14,823
Total other loans | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	3,442		272
Loans - Recorded investment, Collectively evaluated for impairment	57,151		5,049
Allowance for credit loss, Individually evaluated for impairment	394		272
Allowance for credit loss, Collectively evaluated for impairment	56		47
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	1,968,191		1,652,065
Allowance for loan losses	19,998	18,934	15,141	12,206	11,296	12,245
Commercial and industrial | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	16,708		0
Loans - Recorded investment, Collectively evaluated for impairment	1,885,337		1,634,372
Loans - Recorded investment, ASC 310-30 loans	1,902,045		1,634,372
Allowance for credit loss, Individually evaluated for impairment	1,593		0
Allowance for credit loss, Collectively evaluated for impairment	17,878		14,702
Allowance for loan losses	19,471			11,695
Commercial and industrial | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	3,442		272
Loans - Recorded investment, Collectively evaluated for impairment	43,201		4,790
Allowance for credit loss, Individually evaluated for impairment	394		272
Allowance for credit loss, Collectively evaluated for impairment	53		41
Allowance for loan losses	447			311
Commercial and industrial | Unallocated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for loan losses	0			0
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	19,185		7,666
Allowance for loan losses	191	$ 219	272	232	$ 251	$ 228
Consumer | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	0		0
Loans - Recorded investment, Collectively evaluated for impairment	3,976		5,984
Loans - Recorded investment, ASC 310-30 loans	3,976		5,984
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	69		121
Allowance for loan losses	69			73
Consumer | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, Individually evaluated for impairment	0		0
Loans - Recorded investment, Collectively evaluated for impairment	13,950		259
Allowance for credit loss, Individually evaluated for impairment	0		0
Allowance for credit loss, Collectively evaluated for impairment	3		6
Allowance for loan losses	3			7
Consumer | Unallocated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for loan losses	0			0
ASC 310-30 Loans | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	215,370		159,069
Allowance for loan losses	1,866			2,188
ASC 310-30 Loans | Unallocated Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0
Allowance for loan losses	0
ASC 310-30 Loans | Total real estate loans | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Total real estate loans | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	194,608		145,015
Allowance for loan losses	1,667		1,618
ASC 310-30 Loans | Commercial real estate | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Commercial real estate | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	133,778		104,335
Allowance for loan losses	1,556		1,448	1,664
ASC 310-30 Loans | Owner-occupied commercial real estate | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Owner-occupied commercial real estate | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0	0
ASC 310-30 Loans | 1-4 single family residential | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | 1-4 single family residential | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	32,240		27,513
Allowance for loan losses	8		25	25
ASC 310-30 Loans | Construction, land and development | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Construction, land and development | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	28,590		13,167
Allowance for loan losses	103		145	147
ASC 310-30 Loans | Home equity loans and lines of credit | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Home equity loans and lines of credit | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0	0
ASC 310-30 Loans | Total other loans | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Total other loans | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	20,762		14,054
Allowance for loan losses	199		271
ASC 310-30 Loans | Commercial and industrial | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Commercial and industrial | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	19,503		12,631
Allowance for loan losses	80		126	200
ASC 310-30 Loans | Consumer | New Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	0		0
Allowance for loan losses	0		0
ASC 310-30 Loans | Consumer | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans - Recorded investment, ASC 310-30 loans	1,259		1,423
Allowance for loan losses	$ 119		$ 145	$ 152

Allowance for Loan Losses - S_4

Allowance for Loan Losses - Summary of Impaired Loans Evaluated for Specific Reserves (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Total real estate loans | New Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	$ 63	$ 66
Impaired loans - With allowance, Unpaid principal balance	66	66
Impaired loans - With allowance, Related allowance	63	66
Impaired loans - With no allowance, Recorded investment	4,599	1,159
Impaired loans - With no allowance, Unpaid principal balance	4,614	1,159
Total real estate loans | Acquired Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	336
Impaired loans - With allowance, Unpaid principal balance	0	347
Impaired loans - With allowance, Related allowance	0	129
Impaired loans - With no allowance, Recorded investment	4,158	4,319
Impaired loans - With no allowance, Unpaid principal balance	5,753	5,753
Commercial real estate | New Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	459	0
Impaired loans - With no allowance, Unpaid principal balance	470	0
Commercial real estate | Acquired Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	336
Impaired loans - With allowance, Unpaid principal balance	0	347
Impaired loans - With allowance, Related allowance	0	129
Impaired loans - With no allowance, Recorded investment	3,396	3,557
Impaired loans - With no allowance, Unpaid principal balance	4,991	4,991
Owner-occupied commercial real estate | New Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	2,440	0
Impaired loans - With no allowance, Unpaid principal balance	2,440	0
Owner-occupied commercial real estate | Acquired Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	0	0
Impaired loans - With no allowance, Unpaid principal balance	0	0
1-4 single family residential | New Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	1,637	1,096
Impaired loans - With no allowance, Unpaid principal balance	1,641	1,096
1-4 single family residential | Acquired Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	267	267
Impaired loans - With no allowance, Unpaid principal balance	267	267
Construction, land and development | New Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	0	0
Impaired loans - With no allowance, Unpaid principal balance	0	0
Construction, land and development | Acquired Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	0	0
Impaired loans - With no allowance, Unpaid principal balance	0	0
Home equity loans and lines of credit | New Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	63	66
Impaired loans - With allowance, Unpaid principal balance	66	66
Impaired loans - With allowance, Related allowance	63	66
Impaired loans - With no allowance, Recorded investment	63	63
Impaired loans - With no allowance, Unpaid principal balance	63	63
Home equity loans and lines of credit | Acquired Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	495	495
Impaired loans - With no allowance, Unpaid principal balance	495	495
Total other loans | New Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	16,708	0
Impaired loans - With allowance, Unpaid principal balance	16,708	0
Impaired loans - With allowance, Related allowance	1,593	0
Impaired loans - With no allowance, Recorded investment	0	0
Impaired loans - With no allowance, Unpaid principal balance	0	0
Total other loans | Acquired Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	394	272
Impaired loans - With allowance, Unpaid principal balance	394	272
Impaired loans - With allowance, Related allowance	394	272
Impaired loans - With no allowance, Recorded investment	3,047	0
Impaired loans - With no allowance, Unpaid principal balance	6,948	0
Commercial and industrial | New Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	16,708	0
Impaired loans - With allowance, Unpaid principal balance	16,708	0
Impaired loans - With allowance, Related allowance	1,593	0
Impaired loans - With no allowance, Recorded investment	0	0
Impaired loans - With no allowance, Unpaid principal balance	0	0
Commercial and industrial | Acquired Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	394	272
Impaired loans - With allowance, Unpaid principal balance	394	272
Impaired loans - With allowance, Related allowance	394	272
Impaired loans - With no allowance, Recorded investment	3,047	0
Impaired loans - With no allowance, Unpaid principal balance	6,948	0
Consumer | New Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	0	0
Impaired loans - With no allowance, Unpaid principal balance	0	0
Consumer | Acquired Loans
Financing Receivable, Impaired [Line Items]
Impaired loans - With allowance, Recorded investment	0	0
Impaired loans - With allowance, Unpaid principal balance	0	0
Impaired loans - With allowance, Related allowance	0	0
Impaired loans - With no allowance, Recorded investment	0	0
Impaired loans - With no allowance, Unpaid principal balance	$ 0	$ 0

Allowance for Loan Losses - S_5

Allowance for Loan Losses - Summary of Impaired Loans Average Recorded Investment and Interest Income Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Total real estate loans
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance - Average recorded investment	$ 8,788	$ 5,526	$ 6,789	$ 5,601
Impaired loans with no related allowance - Interest income recognized	0	0	0	0
Impaired loans with an allowance - Average recorded investment	63	899	65	1,239
Impaired loans with an allowance - Interest income recognized	0	0	0	0
Commercial real estate
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance - Average recorded investment	3,887	3,629	3,636	3,677
Impaired loans with no related allowance - Interest income recognized	0	0	0	0
Impaired loans with an allowance - Average recorded investment	0	336	0	529
Impaired loans with an allowance - Interest income recognized	0	0	0	0
Owner-occupied commercial real estate
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance - Average recorded investment	2,440	0	1,058	0
Impaired loans with no related allowance - Interest income recognized	0	0	0	0
Impaired loans with an allowance - Average recorded investment	0	0	0	0
Impaired loans with an allowance - Interest income recognized	0	0	0	0
1-4 single family residential
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance - Average recorded investment	1,903	1,363	1,537	1,174
Impaired loans with no related allowance - Interest income recognized	0	0	0	0
Impaired loans with an allowance - Average recorded investment	0	497	0	509
Impaired loans with an allowance - Interest income recognized	0	0	0	0
Construction, land and development
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance - Average recorded investment	0	0	0	0
Impaired loans with no related allowance - Interest income recognized	0	0	0	0
Impaired loans with an allowance - Average recorded investment	0	0	0	0
Impaired loans with an allowance - Interest income recognized	0	0	0	0
Home equity loans and lines of credit
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance - Average recorded investment	558	534	558	750
Impaired loans with no related allowance - Interest income recognized	0	0	0	0
Impaired loans with an allowance - Average recorded investment	63	66	65	201
Impaired loans with an allowance - Interest income recognized	0	0	0	0
Total other loans
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance - Average recorded investment	3,038	0	1,284	0
Impaired loans with no related allowance - Interest income recognized	0	0	0	0
Impaired loans with an allowance - Average recorded investment	17,102	299	11,528	333
Impaired loans with an allowance - Interest income recognized	0	0	0	0
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance - Average recorded investment	3,038	0	1,284	0
Impaired loans with no related allowance - Interest income recognized	0	0	0	0
Impaired loans with an allowance - Average recorded investment	17,102	299	11,528	333
Impaired loans with an allowance - Interest income recognized	0	0	0	0
Consumer
Financing Receivable, Impaired [Line Items]
Impaired loans with no related allowance - Average recorded investment	0	0	0	0
Impaired loans with no related allowance - Interest income recognized	0	0	0	0
Impaired loans with an allowance - Average recorded investment	0	0	0	0
Impaired loans with an allowance - Interest income recognized	$ 0	$ 0	$ 0	$ 0

Goodwill and Intangibles - Sche

Goodwill and Intangibles - Schedule of Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 139,529	$ 81,204
Core deposit intangible	18,950	14,370
Less: Accumulated amortization	(11,737)	(10,702)
Net core deposit intangible	$ 7,213	$ 3,668

Goodwill and Intangibles - Addi

Goodwill and Intangibles - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangibles	$ 371	$ 256	$ 1,035	$ 768

Goodwill and Intangibles - Esti

Goodwill and Intangibles - Estimated Amortization Expense for the Next Five Fiscal Years (Details) $ in Thousands	Sep. 30, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2018	$ 370
2,018	1,481
2,019	968
2,020	818
2,021	$ 818

Derivatives - Additional Inform

Derivatives - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)Derivative	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Derivative [Line Items]
Carrying value of pledged securities	$ 950.4		$ 950.4		$ 834.9
Risk participation agreements entered into | Derivative			3
Proceeds from sale of risk participation agreement			$ 34.3
Interest Rate Swap
Derivative [Line Items]
Carrying value of pledged securities	2.5		2.5
ERROR in label resolution.
Derivative [Line Items]
Customer swap fees in non-interest income	$ 4.4	$ 1.5	$ 10.8	$ 4.8

Derivatives - Summary of Deriva

Derivatives - Summary of Derivatives Outstanding Included in Other Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative assets, Notional	$ 1,893,983
Derivative assets, Fair value	31,698
Derivative liabilities, Notional	1,678,290
Derivative liabilities, Fair value	29,948
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative assets, Notional	250,000
Derivative assets, Fair value	1,750
Derivative liabilities, Notional	0
Derivative liabilities, Fair value	0
Designated as Hedging Instrument | Interest rate contracts - pay fixed, receive floating
Derivatives, Fair Value [Line Items]
Derivative assets, Notional	250,000
Derivative assets, Fair value	1,750
Derivative liabilities, Notional	0
Derivative liabilities, Fair value	0
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative assets, Notional	1,643,983	$ 1,233,004
Derivative assets, Fair value	29,948	11,833
Derivative liabilities, Notional	1,678,290	1,233,004
Derivative liabilities, Fair value	29,948	11,833
Not Designated as Hedging Instrument | Interest rate contracts - pay floating, receive fixed
Derivatives, Fair Value [Line Items]
Derivative assets, Notional	543,748	757,887
Derivative assets, Fair value	6,682	11,678
Derivative liabilities, Notional	1,005,701	380,233
Derivative liabilities, Fair value	25,549	4,180
Not Designated as Hedging Instrument | Interest rate contracts - pay fixed, receive floating
Derivatives, Fair Value [Line Items]
Derivative assets, Notional	1,005,701	380,233
Derivative assets, Fair value	22,954	0
Derivative liabilities, Notional	543,748	757,887
Derivative liabilities, Fair value	4,087	7,498
Not Designated as Hedging Instrument | Interest rate caps purchased
Derivatives, Fair Value [Line Items]
Derivative assets, Notional	94,534	94,884
Derivative assets, Fair value	312	155
Derivative liabilities, Notional	0	0
Derivative liabilities, Fair value	0	0
Not Designated as Hedging Instrument | Interest rate caps sold
Derivatives, Fair Value [Line Items]
Derivative assets, Notional	0	0
Derivative assets, Fair value	0	0
Derivative liabilities, Notional	94,534	94,884
Derivative liabilities, Fair value	312	$ 155
Not Designated as Hedging Instrument | Risk participation agreements
Derivatives, Fair Value [Line Items]
Derivative assets, Notional	0
Derivative assets, Fair value	0
Derivative liabilities, Notional	34,307
Derivative liabilities, Fair value	$ 0

Derivatives - Summary of Gross

Derivatives - Summary of Gross and Net Fair Values of Derivatives Outstanding Included in Other Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Offsetting Liabilities [Line Items]
Net amounts in the consolidated balance sheets	$ 29,948
Interest Rate Swap | Counterparty A
Offsetting Liabilities [Line Items]
Gross amounts of recognized liabilities	24,648	$ 11,833
Gross amounts offset in the consolidated balance sheets	(1,694)	(4,491)
Net amounts in the consolidated balance sheets	22,954	$ 7,342
Interest Rate Swap | Centrally Cleared
Offsetting Liabilities [Line Items]
Gross amounts of recognized liabilities	901
Gross amounts offset in the consolidated balance sheets	(4,989)
Net amounts in the consolidated balance sheets	$ (4,088)

Derivatives - Summary of Gains

Derivatives - Summary of Gains (Losses) on Derivative Instruments (Details) - Interest rate contracts - pay fixed, receive floating - Derivatives designated as cash flow hedges: $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in AOCI	$ 1,313
Amount of Gain (Loss) Reclassified from AOCI to Interest Expense	$ 0

Deposits - Summary of Company's

Deposits - Summary of Company's Deposits by Category (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Noninterest-bearing demand deposits	$ 1,577,741	$ 1,236,685
Interest-bearing demand deposits	1,207,859	1,454,097
Interest-bearing NOW accounts	410,226	363,191
Savings and money market accounts	2,607,093	3,013,237
Time deposits	4,353,196	2,606,717
Total deposits	10,156,115	8,673,927
Time deposits $100,000 and greater	3,005,138	1,983,445
Time deposits greater than $250,000	$ 1,623,796	$ 1,078,702

Deposits - Additional Informati

Deposits - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Aggregate amount of overdraft demand deposits reclassified to loans	$ 2
Aggregate amount of time deposits, Year one	3,460
Aggregate amount of time deposits, Year two	836.9
Aggregate amount of time deposits, Year three	20.4
Aggregate amount of time deposits, Year four	11.6
Aggregate amount of time deposits, Year five	21.6
Brokered deposits through an insured deposits sweep program	419.8	$ 656.4
Brokered certificates of deposit	$ 501.2	$ 85.2

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Unrealized gains (losses) on debt securities available for sale:
Beginning balance, before tax, unrealized gains (losses) on debt securities available for sale	$ (25,353)	$ 25,468	$ 14,402	$ (6,504)
Beginning balance, tax, unrealized gains (losses) on debt securities available for sale	6,326	(9,744)	(5,509)	2,509
Beginning balance, net of tax, unrealized gains (losses) on debt securities available for sale	(26,095)	14,257	(26,095)	14,257	$ (26,095)	$ (19,027)	$ 8,893	$ 14,257	$ 15,724	$ (3,995)
Net unrealized holdings gain (loss) arising during the period, before tax	(11,095)	(967)	(48,163)	31,650
Net unrealized holdings gain (loss) arising during the period, tax effect	2,768	369	12,017	(12,131)
Net unrealized holdings gain (loss) arising during the period, net of tax	(8,327)	(598)	(36,146)	19,519
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	1,677	(1,409)	577	(2,054)
Reclassification from AOCI, Current Period, Tax	(418)	540	(144)	787
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(1,259)	869	(433)	1,267
Cumulative adjustment from adoption of new accounting standards, before tax			(1,587)	0
Cumulative adjustment from adoption of new accounting standards, tax			2,312	0
Cumulative adjustment from adoption of new accounting standards	0	0	725	0
Ending balance, before tax, unrealized gains (losses) on debt securities available for sale	(34,771)	23,092	(34,771)	23,092
Ending balance, tax, unrealized gains (losses) on debt securities available for sale	8,676	(8,835)	8,676	(8,835)
Ending balance, net of tax, unrealized gains (losses) on debt securities available for sale	(26,095)	14,257	(26,095)	14,257
Unrealized gains (losses) on derivative instruments:
Beginning balance, before tax, unrealized gains (losses) on derivative instruments					1,750	124	0	0	0	0
Beginning balance, tax, unrealized gains (losses) on derivative instruments					(437)	(31)	0	0	0	0
Beginning balance, net of tax, unrealized gains (losses) on derivative instruments					$ 1,313	$ 93	$ 0	$ 0	$ 0	$ 0
Net unrealized holdings gain (loss) arising during the period, before tax	1,626	0	1,750	0
Net unrealized holdings gain (loss) arising during the period, tax effect	(406)	0	(437)	0
Net unrealized holdings gain (loss) arising during the period, net of tax	1,220	0	1,313	0
Balance at end of period, before tax	(33,021)	23,092	(33,021)	23,092
Balance at end of period, tax effect	8,239	(8,835)	8,239	(8,835)
Balance at end of period, net of tax	$ (24,782)	$ 14,257	$ (24,782)	$ 14,257

Basic and Diluted Earnings Pe_3

Basic and Diluted Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income available to common stockholders	$ 43,480	$ 32,160	$ 126,313	$ 106,230
Weighted average number of common shares-basic (shares)	46,693,707	43,333,947	46,213,176	42,580,426
Effect of dilutive securities:
Employee stock-based compensation awards and warrants (shares)	2,111,164	2,855,521	2,259,481	3,380,169
Weighted average number of common shares-diluted (shares)	48,804,871	46,189,468	48,472,657	45,960,595
Basic earnings (loss) per share (usd per share)	$ 0.93	$ 0.74	$ 2.73	$ 2.49
Diluted earnings (loss) per share (usd per share)	$ 0.89	$ 0.70	$ 2.61	$ 2.31
Weighted average number of anti-dilutive equity awards (shares)	48,708	41,040	25,332	20,942

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate	23.50%	30.20%	21.70%	19.80%
Excess tax benefit	$ 168	$ 2,100	$ 2,900	$ 18,000

Stock-Based Compensation and _3

Stock-Based Compensation and Other Benefit Plans - Schedule of Option Activity (Detail)	9 Months Ended
	Sep. 30, 2018$ / sharesshares
2009 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, Beginning balance (in shares) | shares	1,314,924
Granted, Options (in shares) | shares	0
Exercised, Options (in shares) | shares	(142,602)
Forfeited, Options (in shares) | shares	0
Expired, Options (in shares) | shares	0
Options outstanding, Ending balance (in shares) | shares	1,172,322
Exercisable, Options (in shares) | shares	1,172,322
Vested, Options (in shares) | shares	1,172,322
Vested and expected to vest, Options (in shares) | shares	1,172,322
Options outstanding, Beginning balance, Weighted average exercise price (usd per share) | $ / shares	$ 20.65
Options granted, Weighted average exercise price (usd per share) | $ / shares	0
Options exercised, Weighted average exercise price (usd per share) | $ / shares	21.15
Options forfeited, Weighted average exercise price (usd per share) | $ / shares	0
Options expired, Weighted average exercise price (usd per share) | $ / shares	0
Options Outstanding, Ending balance, Weighted average exercise price (usd per share) | $ / shares	20.58
Exercisable, Weighted average exercise price (usd per share) | $ / shares	20.58
Vested, Weighted average exercise price (usd per share) | $ / shares	20.58
Vested and expected to vest, Weighted average exercise price (usd per share) | $ / shares	$ 20.58
2013 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, Beginning balance (in shares) | shares	1,424,953
Granted, Options (in shares) | shares	0
Exercised, Options (in shares) | shares	(245,611)
Forfeited, Options (in shares) | shares	0
Expired, Options (in shares) | shares	0
Options outstanding, Ending balance (in shares) | shares	1,179,342
Exercisable, Options (in shares) | shares	1,179,342
Vested, Options (in shares) | shares	1,179,342
Vested and expected to vest, Options (in shares) | shares	1,179,342
Options outstanding, Beginning balance, Weighted average exercise price (usd per share) | $ / shares	$ 20.79
Options granted, Weighted average exercise price (usd per share) | $ / shares	0
Options exercised, Weighted average exercise price (usd per share) | $ / shares	20.53
Options forfeited, Weighted average exercise price (usd per share) | $ / shares	0
Options expired, Weighted average exercise price (usd per share) | $ / shares	0
Options Outstanding, Ending balance, Weighted average exercise price (usd per share) | $ / shares	20.84
Exercisable, Weighted average exercise price (usd per share) | $ / shares	20.84
Vested, Weighted average exercise price (usd per share) | $ / shares	20.84
Vested and expected to vest, Weighted average exercise price (usd per share) | $ / shares	$ 20.84
2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, Beginning balance (in shares) | shares	762,500
Granted, Options (in shares) | shares	0
Exercised, Options (in shares) | shares	0
Forfeited, Options (in shares) | shares	(30,000)
Expired, Options (in shares) | shares	0
Options outstanding, Ending balance (in shares) | shares	732,500
Exercisable, Options (in shares) | shares	0
Vested, Options (in shares) | shares	0
Vested and expected to vest, Options (in shares) | shares	732,500
Options outstanding, Beginning balance, Weighted average exercise price (usd per share) | $ / shares	$ 36.64
Options granted, Weighted average exercise price (usd per share) | $ / shares	0
Options exercised, Weighted average exercise price (usd per share) | $ / shares	0
Options forfeited, Weighted average exercise price (usd per share) | $ / shares	36.11
Options expired, Weighted average exercise price (usd per share) | $ / shares	0
Options Outstanding, Ending balance, Weighted average exercise price (usd per share) | $ / shares	36.66
Exercisable, Weighted average exercise price (usd per share) | $ / shares	0
Vested, Weighted average exercise price (usd per share) | $ / shares	0
Vested and expected to vest, Weighted average exercise price (usd per share) | $ / shares	$ 36.66

Stock-Based Compensation and _4

Stock-Based Compensation and Other Benefit Plans - Additional Information (Detail) - USD ($)	Mar. 21, 2018	Feb. 21, 2018	Feb. 07, 2017	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
2009 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to shares awards				$ 0	$ 0
2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to shares awards				$ 3,700,000	$ 3,700,000
Weighted-average life over which expense is expected to be recognized (years)					2 years 11 months 1 day
Restricted Shares | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average life over which expense is expected to be recognized (years)					9 months 11 days	1 year 4 months 28 days
Awards granted (in shares)					0
Share-based compensation expense					$ 1,968,000	$ 2,570,000
Restricted Stock Units (RSUs) | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average life over which expense is expected to be recognized (years)					4 years 18 days	3 years 7 months 24 days
Awards granted (in shares)					72,567
Share-based compensation expense					$ 1,710,000	$ 863,000
Employee Restricted Stock Units | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)				53,552
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				5 years	5 years
Award fair value				$ 3,000,000
Performance Restricted Stock Unit Awards | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average life over which expense is expected to be recognized (years)					1 year 11 months 16 days	2 years 3 months
Awards granted (in shares)					84,836
Share-based compensation expense					$ 1,855,000	$ 649,000
Cash phantom units (CPUs) | Long-Term Incentive Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
CPU, par value (in dollars per share)	$ 0.001
Award fair value	$ 1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period	3 years
Share-based compensation expense				$ 91,000	$ 193,000
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
CPU, par value (in dollars per share)				$ 0.001	$ 0.001		$ 0.001
Directors | Restricted Stock Units (RSUs) | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)		19,015
Award fair value		$ 1,100,000
Executive | Restricted Stock Units (RSUs) | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award fair value	$ 4,800,000
Vest on March 30, 2017 | Directors | Restricted Stock Units (RSUs) | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		25.00%
Vest on June 30, 2017 | Directors | Restricted Stock Units (RSUs) | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		25.00%
Vest on September 30, 2017 | Directors | Restricted Stock Units (RSUs) | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage			25.00%
Vest on December 31, 2017 | Directors | Restricted Stock Units (RSUs) | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage			25.00%
Minimum | Performance Restricted Stock Unit Awards | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage					0.00%
Minimum | Cash phantom units (CPUs) | Long-Term Incentive Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	18,050
Minimum | Executive | Restricted Stock Units (RSUs) | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	84,836
Maximum | Performance Restricted Stock Unit Awards | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage					125.00%
Maximum | Cash phantom units (CPUs) | Long-Term Incentive Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	22,562
Award fair value	$ 1,300,000
Maximum | Executive | Restricted Stock Units (RSUs) | 2016 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted (in shares)	106,043
Award fair value	$ 5,900,000

Stock-Based Compensation and _5

Stock-Based Compensation and Other Benefit Plans - Schedule of Share-based Compensation by Award (Details) - 2016 Stock Incentive Plan	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares) | shares	96,133
Granted (in shares) | shares	0
Vested (in shares) | shares	0
Forfeited (in shares) | shares	0
Ending balance (in shares) | shares	96,133
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance, weighted average grant date fair value (in dollars per share) | $ / shares	$ 42.23
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	0
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	0
Forfeitures, weighted average grant date fair value (in dollars per share) | $ / shares	0
Ending balance, weighted average grant date fair value (in dollars per share) | $ / shares	$ 42.23
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares) | shares	88,015
Granted (in shares) | shares	72,567
Vested (in shares) | shares	(20,459)
Forfeited (in shares) | shares	(5,300)
Ending balance (in shares) | shares	134,823
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance, weighted average grant date fair value (in dollars per share) | $ / shares	$ 50.34
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	56.52
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	52.38
Forfeitures, weighted average grant date fair value (in dollars per share) | $ / shares	52.62
Ending balance, weighted average grant date fair value (in dollars per share) | $ / shares	$ 53.27
Performance Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares) | shares	73,144
Granted (in shares) | shares	84,836
Vested (in shares) | shares	0
Forfeited (in shares) | shares	0
Ending balance (in shares) | shares	157,980
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance, weighted average grant date fair value (in dollars per share) | $ / shares	$ 47.85
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	56.10
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	0
Forfeitures, weighted average grant date fair value (in dollars per share) | $ / shares	0
Ending balance, weighted average grant date fair value (in dollars per share) | $ / shares	$ 52.28

Stock-Based Compensation and _6

Stock-Based Compensation and Other Benefit Plans - Schedule of Stock-Based Compensation Expense (Details) - 2016 Stock Incentive Plan - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average life over which expense is expected to be recognized (years)	2 years 11 months 1 day
Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,968	$ 2,570
Unrecognized compensation expense related to stock-based compensation	$ 1,145	$ 4,216
Weighted-average life over which expense is expected to be recognized (years)	9 months 11 days	1 year 4 months 28 days
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,710	$ 863
Unrecognized compensation expense related to stock-based compensation	$ 6,183	$ 1,067
Weighted-average life over which expense is expected to be recognized (years)	4 years 18 days	3 years 7 months 24 days
Performance Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,855	$ 649
Unrecognized compensation expense related to stock-based compensation	$ 5,437	$ 2,851
Weighted-average life over which expense is expected to be recognized (years)	1 year 11 months 16 days	2 years 3 months

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Reserve for unfunded commitments	$ 1.5	$ 1.1

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Unfunded Commitments (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Unfunded credit extension commitments	$ 1,985,181	$ 1,544,512
Commitments to fund loans
Line of Credit Facility [Line Items]
Unfunded credit extension commitments	1,159,541	926,405
Unused lines of credit
Line of Credit Facility [Line Items]
Unfunded credit extension commitments	774,695	571,587
Commercial and standby letters of credit
Line of Credit Facility [Line Items]
Unfunded credit extension commitments	$ 50,945	$ 46,520

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of financial assets between levels	$ 0	$ 0
Fair Value, Measurements, Recurring
Assets:
Assets, fair value	2,378,417,000	2,378,417,000	$ 2,132,636,000
Liabilities:
Liabilities, fair value	29,949,000	29,949,000	11,833,000
Fair Value, Measurements, Recurring | Derivative liabilities | Interest Rate Swap
Liabilities:
Liabilities, fair value	29,949,000	29,949,000	11,833,000
Fair Value, Measurements, Recurring | Level 1
Assets:
Assets, fair value	65,556,000	65,556,000	68,924,000
Liabilities:
Liabilities, fair value	0	0	0
Fair Value, Measurements, Recurring | Level 1 | Derivative liabilities | Interest Rate Swap
Liabilities:
Liabilities, fair value	0	0	0
Fair Value, Measurements, Recurring | Level 2
Assets:
Assets, fair value	2,312,861,000	2,312,861,000	2,063,712,000
Liabilities:
Liabilities, fair value	29,949,000	29,949,000	11,833,000
Fair Value, Measurements, Recurring | Level 2 | Derivative liabilities | Interest Rate Swap
Liabilities:
Liabilities, fair value	29,949,000	29,949,000	11,833,000
Fair Value, Measurements, Recurring | Level 3
Assets:
Assets, fair value	0	0	0
Liabilities:
Liabilities, fair value	0	0	0
Fair Value, Measurements, Recurring | Level 3 | Derivative liabilities | Interest Rate Swap
Liabilities:
Liabilities, fair value	0	0	0
Fair Value, Measurements, Recurring | U.S. Government agencies and sponsored enterprises obligations
Assets:
Assets, fair value	84,232,000	84,232,000	42,838,000
Fair Value, Measurements, Recurring | U.S. Government agencies and sponsored enterprises obligations | Level 1
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | U.S. Government agencies and sponsored enterprises obligations | Level 2
Assets:
Assets, fair value	84,232,000	84,232,000	42,838,000
Fair Value, Measurements, Recurring | U.S. Government agencies and sponsored enterprises obligations | Level 3
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | U.S. Government agencies and sponsored enterprises mortgage-backed securities
Assets:
Assets, fair value	604,158,000	604,158,000	595,237,000
Fair Value, Measurements, Recurring | U.S. Government agencies and sponsored enterprises mortgage-backed securities | Level 1
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | U.S. Government agencies and sponsored enterprises mortgage-backed securities | Level 2
Assets:
Assets, fair value	604,158,000	604,158,000	595,237,000
Fair Value, Measurements, Recurring | U.S. Government agencies and sponsored enterprises mortgage-backed securities | Level 3
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | State and municipal obligations
Assets:
Assets, fair value	22,882,000	22,882,000	26,172,000
Fair Value, Measurements, Recurring | State and municipal obligations | Level 1
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | State and municipal obligations | Level 2
Assets:
Assets, fair value	22,882,000	22,882,000	26,172,000
Fair Value, Measurements, Recurring | State and municipal obligations | Level 3
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | Asset-backed securities
Assets:
Assets, fair value	778,322,000	778,322,000	610,546,000
Fair Value, Measurements, Recurring | Asset-backed securities | Level 1
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | Asset-backed securities | Level 2
Assets:
Assets, fair value	778,322,000	778,322,000	610,546,000
Fair Value, Measurements, Recurring | Asset-backed securities | Level 3
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | Corporate bonds and other debt securities
Assets:
Assets, fair value	786,109,000	786,109,000	755,903,000
Fair Value, Measurements, Recurring | Corporate bonds and other debt securities | Level 1
Assets:
Assets, fair value	52,966,000	52,966,000	55,970,000
Fair Value, Measurements, Recurring | Corporate bonds and other debt securities | Level 2
Assets:
Assets, fair value	733,143,000	733,143,000	699,933,000
Fair Value, Measurements, Recurring | Corporate bonds and other debt securities | Level 3
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | Preferred stock and other equity securities
Assets:
Assets, fair value	71,015,000	71,015,000	90,107,000
Fair Value, Measurements, Recurring | Preferred stock and other equity securities | Level 1
Assets:
Assets, fair value	12,590,000	12,590,000	12,954,000
Fair Value, Measurements, Recurring | Preferred stock and other equity securities | Level 2
Assets:
Assets, fair value	58,425,000	58,425,000	77,153,000
Fair Value, Measurements, Recurring | Preferred stock and other equity securities | Level 3
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | Derivative assets | Interest Rate Swap
Assets:
Assets, fair value	31,699,000	31,699,000	11,833,000
Fair Value, Measurements, Recurring | Derivative assets | Level 1 | Interest Rate Swap
Assets:
Assets, fair value	0	0	0
Fair Value, Measurements, Recurring | Derivative assets | Level 2 | Interest Rate Swap
Assets:
Assets, fair value	31,699,000	31,699,000	11,833,000
Fair Value, Measurements, Recurring | Derivative assets | Level 3 | Interest Rate Swap
Assets:
Assets, fair value	$ 0	$ 0	$ 0

Fair Value Measurements - Signi

Fair Value Measurements - Significant Unobservable Inputs in Fair Value Measurement Level 3 Assets and Liabilities (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned, fair value	$ 10,534	$ 14,906
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	9,185,518	7,877,094
Fair Value, Measurements, Nonrecurring | Level 3 | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans, fair value	28,969	6,153
Fair Value, Measurements, Nonrecurring | Level 3 | Other real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned, fair value	$ 10,534	$ 14,906
Range (Weighted Average)	10.00%
Fair Value, Measurements, Nonrecurring | Level 3 | Minimum | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Weighted Average)	0.00%
Fair Value, Measurements, Nonrecurring | Level 3 | Maximum | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Weighted Average)	100.00%
Fair Value, Measurements, Nonrecurring | Level 3 | Weighted Average | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Range (Weighted Average)	7.10%

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value, Assets Measured on Nonrecurring Basis (Details) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Negative valuation adjustments	$ (122)	$ 0	$ (1,715)	$ 0
Foreclosed Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Negative valuation adjustments	$ (9)	$ (54)	$ (1,106)	$ (437)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Carrying Amounts and Estimated Fair Values, as well as the Level Within the Fair Value Hierarchy (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 200,509	$ 115,921	$ 112,427	$ 83,876
Available for sale debt securities	2,275,703	2,030,696
Preferred stocks and other equity securities	71,015	90,107
FHLB and other bank stock	65,847	56,881
Loans held for sale	980	12,736
Bank-owned life insurance	215,421	201,069
Derivative assets	31,698
Deposits	10,156,115	8,673,927
Advances from the FHLB and other borrowings	825,558	749,113
Derivative liabilities	29,948
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	200,509	115,921
Available for sale debt securities	2,275,703	2,030,696
Preferred stocks and other equity securities	71,015	90,107
FHLB and other bank stock	65,847	56,881
Loans, net	9,263,660	7,930,639
Loans held for sale	980	12,736
Bank-owned life insurance	215,421	201,069
Derivative assets	31,699	11,833
Deposits	10,156,115	8,673,927
Advances from the FHLB and other borrowings	825,558	749,113
Derivative liabilities	29,949	11,833
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	200,509	115,921
Available for sale debt securities	2,275,703	2,130,696
Preferred stocks and other equity securities	71,015	90,107
FHLB and other bank stock	65,847	56,881
Loans, net	9,185,518	7,877,094
Loans held for sale	980	12,736
Bank-owned life insurance	215,421	201,069
Derivative assets	31,699	11,833
Deposits	10,133,649	8,664,125
Advances from the FHLB and other borrowings	853,004	740,941
Derivative liabilities	29,949	11,833
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	200,509	115,921
Available for sale debt securities	52,966	55,970
Preferred stocks and other equity securities	12,590	12,954
FHLB and other bank stock	0	0
Loans, net	0	0
Loans held for sale	0	0
Bank-owned life insurance	0	0
Derivative assets	0	0
Deposits	0	0
Advances from the FHLB and other borrowings	0	0
Derivative liabilities	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Available for sale debt securities	2,222,737	1,974,726
Preferred stocks and other equity securities	58,425	77,153
FHLB and other bank stock	65,847	56,881
Loans, net	0	0
Loans held for sale	980	12,736
Bank-owned life insurance	215,421	201,069
Derivative assets	31,699	11,833
Deposits	10,133,649	8,664,125
Advances from the FHLB and other borrowings	853,004	740,941
Derivative liabilities	29,949	11,833
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Available for sale debt securities	0	0
Preferred stocks and other equity securities	0	0
FHLB and other bank stock	0	0
Loans, net	9,185,518	7,877,094
Loans held for sale	0	0
Bank-owned life insurance	0	0
Derivative assets	0	0
Deposits	0	0
Advances from the FHLB and other borrowings	0	0
Derivative liabilities	$ 0	$ 0

Revenue Recognition - Schedule

Revenue Recognition - Schedule of Disaggregation of Noninterest Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Service charges and fees	$ 1,266	$ 941	$ 3,503	$ 2,758
Other noninterest income	1,068	2,218	3,775	8,754
Gain (loss) on sale of loans	142	1,233	92	2,199
Gain (loss) on sale of fixed assets	(24)	6	(13)	7
Fees and Commissions	5,043	2,831	13,261	8,374
Bank-owned life insurance income	1,439	1,422	4,228	4,250
Income from resolution of acquired assets	202	466	603	1,548
Gain (loss) on investment securities	(184)	690	(1,472)	1,722
Noninterest Income, Out Of Scope Of Topic 606	6,618	6,648	16,699	18,100
Noninterest Income	8,764	8,425	23,941	27,285
Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Service charges and fees	1,266	941	3,503	2,758
Noninterest Income (in-scope of Topic 606)	2,146	1,777	7,242	9,185
Accounting Standards Update 2014-09 | NSF/OD Fees
Disaggregation of Revenue [Line Items]
Service charges and fees	416	328	1,149	1,113
Accounting Standards Update 2014-09 | Fees on deposit accounts
Disaggregation of Revenue [Line Items]
Service charges and fees	850	613	2,354	1,645
Accounting Standards Update 2014-09 | ATM and debit card income
Disaggregation of Revenue [Line Items]
Other noninterest income	261	551	1,571	1,762
Accounting Standards Update 2014-09 | Safe deposit box
Disaggregation of Revenue [Line Items]
Other noninterest income	19	18	70	67
Accounting Standards Update 2014-09 | Merchant revenue
Disaggregation of Revenue [Line Items]
Other noninterest income	214	188	633	531
Accounting Standards Update 2014-09 | Ancillary fees and income
Disaggregation of Revenue [Line Items]
Other noninterest income	195	88	457	266
Accounting Standards Update 2014-09 | CD custody income and fees
Disaggregation of Revenue [Line Items]
Other noninterest income	161	0	384	0
Accounting Standards Update 2014-09 | Misc other income
Disaggregation of Revenue [Line Items]
Other noninterest income	100	134	581	3,922
Accounting Standards Update 2014-09 | Misc other income
Disaggregation of Revenue [Line Items]
Other noninterest income	$ (70)	$ (143)	$ 43	$ (121)