First Interstate BancSystem (FIBK) 10-Q 8 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 30, 2017shares
Entity Registrant Name	FIRST INTERSTATE BANCSYSTEM INC
Entity Central Index Key	860,413
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Class A Common Stock
Entity Common Stock, Shares Outstanding	33,383,364
Class B Common Stock
Entity Common Stock, Shares Outstanding	23,072,524

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 201,124	$ 146,779
Interest bearing deposits in banks	681,564	635,149
Federal funds sold	146	95
Total cash and cash equivalents	882,834	782,023
Investment securities:
Available-for-sale	2,111,697	1,611,698
Held-to-maturity (estimated fair values of $510,405 and $513,273 at September 30, 2017 and December 31, 2016, respectively)	505,985	512,770
Total investment securities	2,617,682	2,124,468
Loans held for investment	7,502,387	5,416,750
Mortgage loans held for sale	49,729	61,794
Total loans	7,552,116	5,478,544
Less allowance for loan losses	74,572	76,214
Net loans	7,477,544	5,402,330
Goodwill	445,028	212,820
Company-owned life insurance	258,929	198,116
Premises and equipment, net of accumulated depreciation	242,940	194,457
Accrued interest receivable	40,621	29,852
Mortgage servicing rights, net of accumulated amortization and impairment reserve	24,372	18,457
Core deposit intangibles, net of accumulated amortization	50,971	9,648
Other real estate owned (“OREO”)	10,344	10,019
Deferred tax asset, net	5,343	0
Other assets	149,865	81,705
Total assets	12,206,473	9,063,895
Deposits:
Non-interest bearing	2,965,332	1,906,257
Interest bearing	6,968,136	5,469,853
Total deposits	9,933,468	7,376,110
Securities sold under repurchase agreements	635,288	537,556
Accounts payable and accrued expenses	92,135	44,923
Accrued interest payable	5,648	5,421
Deferred tax liability	0	6,839
Long-term debt	8,039	27,970
Other borrowed funds	30,008	6
Subordinated debentures held by subsidiary trusts	82,477	82,477
Total liabilities	10,787,063	8,081,302
Stockholders’ equity:
Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; no shares issued and outstanding as of September 30, 2017 or December 31, 2016	0	0
Common stock	686,508	296,071
Retained earnings	731,879	694,650
Accumulated other comprehensive income (loss), net	1,023	(8,128)
Total stockholders’ equity	1,419,410	982,593
Total liabilities and stockholders’ equity	$ 12,206,473	$ 9,063,895

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Investment securities:
Estimated Fair Value	$ 510,405	$ 513,273
Stockholders' equity:
Nonvoting noncumulative preferred stock, authorized shares	100,000	100,000
Nonvoting noncumulative preferred stock, issued shares	0	0
Nonvoting noncumulative preferred stock, outstanding shares	0	0

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Interest income:
Interest and fees on loans	$ 94,019	$ 65,626	$ 231,643	$ 191,076
Interest and dividends on investment securities:
Taxable	11,634	7,878	30,139	23,898
Exempt from federal taxes	795	820	2,442	2,557
Interest on deposits in banks	2,314	607	4,859	1,734
Interest on federal funds sold	3	4	8	9
Total interest income	108,765	74,935	269,091	219,274
Interest expense:
Interest on deposits	6,197	3,099	15,326	9,435
Interest on securities sold under repurchase agreements	350	100	870	282
Interest on other debt	608	457	1,542	1,357
Interest on subordinated debentures held by subsidiary trusts	819	698	2,346	2,036
Total interest expense	7,974	4,354	20,084	13,110
Net interest income	100,791	70,581	249,007	206,164
Provision for loan losses	3,443	2,363	7,528	8,913
Net interest income after provision for loan losses	97,348	68,218	241,479	197,251
Non-interest income:
Payment services revenues	12,366	9,019	31,036	25,658
Mortgage banking revenues	8,251	11,303	22,442	28,311
Wealth management revenues	5,544	4,995	15,641	14,736
Service charges on deposit accounts	5,904	4,692	15,314	13,781
Other service charges, commissions and fees	3,584	2,628	9,618	8,081
Loss on termination of interest rate swap	(1,128)	0	(1,128)	0
Investment securities gains (losses), net	771	225	778	312
Other income	2,982	2,299	10,860	7,049
Non-recurring litigation recovery	0	0	0	3,750
Total non-interest income	38,274	35,161	104,561	101,678
Non-interest expense:
Salaries and wages	34,662	26,908	88,440	79,755
Employee benefits	10,185	8,610	29,612	26,285
Outsourced technology services	6,569	5,211	17,869	14,843
Occupancy, net	6,059	4,413	16,028	13,361
Furniture and equipment	3,151	2,398	8,163	7,114
OREO expense, net of income	242	8	228	109
Professional fees	1,888	1,191	4,712	3,635
FDIC insurance premiums	1,666	1,212	3,327	3,668
Mortgage servicing rights amortization	816	854	2,135	2,210
Mortgage servicing rights impairment (recovery)	(12)	(16)	(84)	(21)
Core deposit intangibles amortization	1,885	875	3,577	2,529
Other expenses	14,529	12,542	40,887	36,740
Acquisition related expenses	13,016	1,197	23,854	1,197
Total non-interest expense	94,656	65,403	238,748	191,425
Income before income tax expense	40,966	37,976	107,292	107,504
Income tax expense	13,707	12,783	35,039	36,633
Net income	$ 27,259	$ 25,193	$ 72,253	$ 70,871
Basic earnings per common share (in dollars per share)	$ 0.49	$ 0.57	$ 1.46	$ 1.59
Diluted earnings per common share (in dollars per share)	$ 0.48	$ 0.56	$ 1.45	$ 1.58

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 27,259	$ 25,193	$ 72,253	$ 70,871
Other comprehensive income, before tax:
Change in net unrealized (losses) gains during period	(1,812)	(3,430)	15,553	15,241
Reclassification adjustment for net (gains) losses included in income	(771)	(225)	(778)	(312)
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity	465	490	1,394	1,394
Unrealized loss (gain) on derivatives	(658)	512	(1,095)	(2,490)
Reclassification adjustment for derivatives net (gains) losses included in income	1,128	0	1,128	0
Defined benefit post-retirement benefits plans:
Change in net actuarial (gain) loss	(176)	15	(1,090)	43
Other comprehensive income, before tax	(1,824)	(2,638)	15,112	13,876
Deferred tax expense (benefit) related to other comprehensive income	851	1,038	(5,961)	(5,460)
Other comprehensive (loss) income, net of tax	(973)	(1,600)	9,151	8,416
Comprehensive income, net of tax	$ 26,286	$ 23,593	$ 81,404	$ 79,287

Consolidated Statement of Chang

Consolidated Statement of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Retained earnings	Accumulated other comprehensive income (loss)
Beginning Balance at Dec. 31, 2015	$ 950,493	$ 311,720	$ 638,367	$ 406
Comprehensive income:
Net income	70,871		70,871
Other comprehensive income, net of tax expense	8,416			8,416
Common stock transactions:
Common shares purchased and retired	(26,119)	(26,119)
Stock options exercised, net of shares tendered in payment of option price and income tax withholding amounts	3,657	3,657
Stock-based compensation expense	3,350	3,350
Tax benefit of stock-based compensation	1,352	1,352
Cash dividends declared:
Common cash dividend declared	(29,516)		(29,516)
Ending Balance at Sep. 30, 2016	982,504	293,960	679,722	8,822
Beginning Balance at Dec. 31, 2016	982,593	296,071	694,650	(8,128)
Comprehensive income:
Net income	72,253		72,253
Other comprehensive income, net of tax expense	9,151			9,151
Common stock transactions:
Common shares purchased and retired	(938)	(938)
Common shares issued	385,969	385,969
Stock options exercised, net of shares tendered in payment of option price and income tax withholding amounts	1,988	1,988
Stock-based compensation expense	3,418	3,418
Cash dividends declared:
Common cash dividend declared	(35,024)		(35,024)
Ending Balance at Sep. 30, 2017	$ 1,419,410	$ 686,508	$ 731,879	$ 1,023

Consolidated Statement of Chan7

Consolidated Statement of Changes in Stockholders' Equity (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Common stock
Common stock transactions:
Common shares purchased and retired	22,727	998,135
Common shares issued	11,267,676	16,085
Non-vested common shares issued	134,044	189,624
Non-vested common shares forfeited	30,070	25,984
Stock options exercised (in shares)	180,789	270,183
Shares tendered in payment of option price and income tax withholding amounts	56,082	94,902
Retained earnings
Cash dividends declared:
Common dividends (in dollars per share)	$ 0.72	$ 0.66

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net income	$ 72,253	$ 70,871
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	7,528	8,913
Net loss on disposal of premises and equipment	0	492
Depreciation and amortization	17,920	14,482
Net premium amortization on investment securities	8,464	9,423
Net gain on investment securities transactions	(778)	(312)
Realized and unrealized net gains on mortgage banking activities	(15,353)	(15,126)
Net gain on sale of OREO	(375)	(693)
Write-downs of OREO and other assets pending disposal	294	621
Net (gain) on sale of Health Savings Accounts	(3,068)	0
Mortgage servicing rights recovery	(84)	(21)
Deferred income tax expense (benefit)	19,771	(344)
Net increase in cash surrender value of company-owned life insurance	(3,775)	(3,431)
Stock-based compensation expense	3,418	3,350
Tax benefits from stock-based compensation expense	0	1,352
Excess tax benefits from stock-based compensation expense	0	(1,126)
Originations of mortgage loans held for sale	(980,551)	(799,445)
Proceeds from sales of mortgage loans held for sale	992,409	795,527
Changes in operating assets and liabilities, net of effects of acquisition:
(Increase) decrease in interest receivable	(3,164)	(2,203)
Decrease (increase) in other assets	(4,784)	(2,644)
Increase in accrued interest payable	227	646
Increase (decrease) in accounts payable and accrued expenses	(15,658)	(1,278)
Net cash provided by operating activities	94,694	79,054
Cash flows from investing activities:
Purchase of investment securities, Held-to-maturity	(12,793)	(18,170)
Purchase of investment securities, Available-for-sale	(386,527)	(626,574)
Proceeds from maturities and paydowns of held-to-maturity investment securities	76,027	86,306
Proceeds from maturities and paydowns of available-for-sale investment securities	319,958	652,064
Extensions of credit to customers, net of repayments	(20,885)	(203,216)
Recoveries of loans charged-off	6,452	6,363
Proceeds from sale of OREO	4,150	3,352
Acquisition of intangible assets	(28,013)	0
Proceeds from the sale of Health Savings Accounts	6,138	0
Proceeds from sale of loan production office	0	932
Acquisition of bank and bank holding company, net of cash and cash equivalents received	91,775	18,554
Capital expenditures, net of sales	(12,237)	(5,113)
Net cash provided by (used in) investing activities	44,045	(85,502)
Cash flows from financing activities:
Net increase (decrease) in deposits	(111,618)	30,057
Net increase (decrease) in securities sold under repurchase agreements	97,732	(51,917)
Net increase in other borrowed funds	10,000	6
Repayments of long-term debt	(69)	(49)
Advances on long-term debt	0	113
Proceeds from issuance of common stock	1,988	3,657
Excess tax benefits from stock-based compensation expense	0	1,126
Purchase and retirement of common stock	(938)	(26,119)
Dividends paid to common stockholders	(35,024)	(29,516)
Net cash used in financing activities	(37,929)	(72,642)
Net increases (decrease) in cash and cash equivalents	100,811	(79,090)
Cash and cash equivalents at beginning of period	782,023	780,457
Cash and cash equivalents at end of period	882,834	701,367
Supplemental disclosures of cash flow information:
Cash paid during the period for income taxes	24,279	40,416
Cash paid during the period for interest expense	19,857	12,448
Noncash or Part Noncash Acquisition, Value of Assets Acquired [Abstract]
Transfer of loans to loans held for sale	6,270	50
Transfer from long-term debt to other borrowed funds	20,000	0
Transfer of loans to other real estate owned	3,182	5,335
Capitalization of internally originated mortgage servicing rights	4,147	3,890
Investment securities available for sale	424,302	0
Investment securities held to maturity	57,307	0
Loans held for sale	10,259	0
Loans	2,080,374	0
Premises and equipment	46,732	0
Goodwill	232,208	0
Core deposit intangible	47,968	0
Mortgage servicing rights	3,491	0
Interest receivable	7,605	0
Company-owned life insurance	57,038	0
Deferred tax assets	25,992	0
Other real estate owned	1,192	0
Other assets	31,572	0
Total noncash assets acquired	3,026,040	0
Liabilities assumed:
Deposits	2,668,976	0
Accounts payable and accrued expenses	62,870	0
Total liabilities assumed	$ 2,731,846	$ 0

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation In the opinion of management, the accompanying unaudited consolidated financial statements of First Interstate BancSystem, Inc. and subsidiaries (the “Company”) contain all adjustments (all of which are of a normal recurring nature) necessary to present fairly the financial position of the Company at September 30, 2017 and December 31, 2016 , the results of operations for each of the three and nine month periods ended September 30, 2017 and 2016 , and cash flows and changes in stockholders' equity for each of the nine month periods ended September 30, 2017 and 2016 , in conformity with U.S. generally accepted accounting principles. The balance sheet information at December 31, 2016 is derived from audited consolidated financial statements. Certain reclassifications, none of which were material, have been made to conform prior year financial statements to the September 30, 2017 presentation. These reclassifications did not change previously reported net income or stockholders’ equity. These unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 . Operating results for the three and nine months ended September 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017 .

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Acquisitions	Acquisitions Cascade Bancorp. On November 17, 2016 , the Company entered into an agreement and plan of merger (the “Agreement”) to acquire all of the outstanding stock of Cascade Bancorp (“Cascade”), parent company of Bank of the Cascades, an Oregon-based community bank with 46 banking offices across Oregon, Idaho, and Washington. This transaction solidifies the Company's ability to strategically expand its community banking footprint in the Northwest corridor of the United States. The merger was completed on May 30, 2017 . Holders of each share of Cascade common stock received 0.14864 shares of First Interstate Class A common stock and $ 1.91 in cash, without interest, for each share of Cascade common stock. In connection with the merger, the Company issued approximately 11.3 million shares of First Interstate Class A common stock, which was valued at $ 34.30 per share, which was the closing price of First Interstate Class A common stock on the acquisition date. Cash paid by First Interstate was approximately $ 155.0 million, which included the cash portion of the merger consideration and the cash in lieu of fractional shares that Cascade Bancorp shareholders would have otherwise been entitled to receive. Total consideration exchanged in connection with the merger amounted to $ 541.0 million. All “in-the-money” Cascade options and all Cascade restricted stock units outstanding immediately prior to the transaction close were canceled in exchange for the right to receive a cash payment as provided in the Agreement. The Company paid approximately $ 9.3 million in cash related to Cascade options and restricted stock units, which was included in the consideration paid. Unvested Cascade restricted stock awards outstanding immediately prior to the transaction close were canceled in exchange for the right to receive a cash payment and Company shares as provided in the Agreement. The Company paid a total of approximately $ 2.2 million in cash and issued approximately 168 thousand Company shares, valued at $ 34.30 per share, related to Cascade unvested restricted stock awards. Of the cash paid and shares issued related to Cascade unvested restricted stock awards, approximately $ 2.4 million was allocated to expense and excluded from consideration paid due to the acceleration of award vesting at the Company’s discretion. The remaining balance of approximately $ 5.5 million related to unvested Cascade restricted stock awards is included in the consideration paid. The assets and liabilities of Cascade were recorded in the Company's consolidated financial statements on a provisional basis at their estimated fair values as of the acquisition date and will be finalized in the coming months. The excess value of the consideration paid over the fair value of assets acquired and liabilities assumed is recorded as provisional goodwill. The preliminary purchase price allocation resulted in provisional goodwill of $232.2 million , which is not deductible for income tax purposes. Goodwill resulting from the acquisition was allocated to the Company's one operating segment, community banking, and consists largely of the synergies and economies of scale expected from combining the operations of Cascade and the Company. The following table summarizes the consideration paid, fair values of the Cascade assets acquired and liabilities assumed, and the resulting goodwill. Due to the recent closing of the transaction, all amounts reported are provisional pending the review of valuations obtained from third parties. As Recorded Fair Value As Recorded As of May 30, 2017 by Cascade Adjustments by the Company Assets acquired: Cash and cash equivalents $ 246,804 $ — $ 246,804 Investment securities 476,733 4,876 (1) 481,609 Loans held for investment 2,112,077 (31,703 ) (2) 2,080,374 Mortgage loans held for sale 10,253 6 (2) 10,259 Allowance for loan loss (23,974 ) 23,974 (3) — Premises and equipment 46,554 178 (4) 46,732 Other real estate owned ("OREO") 1,192 — 1,192 Core deposit intangible — 47,968 (5) 47,968 Deferred tax assets 47,653 (21,661 ) (6) 25,992 Other assets 98,570 1,136 (7) 99,706 Total assets acquired 3,015,862 24,774 3,040,636 Liabilities assumed: Deposits 2,669,910 (934 ) (8) 2,668,976 Accounts Payable and Accrued Expense 62,150 720 (9) 62,870 Total liabilities assumed 2,732,060 (214 ) 2,731,846 Net assets acquired $ 283,802 $ 24,988 $ 308,790 Consideration paid: Cash $ 155,029 Class A common stock 385,969 Total consideration paid 540,998 Goodwill $ 232,208 Explanation of fair value adjustments. Note that certain marks have been updated since prior quarter, and certain balances have been reclassified, none of which are material: (1) Write up of the book value of investments to their estimated fair values on the date of acquisition based upon quotes obtained from an independent third party pricing service. (2) Write down of the book value of loans to their estimated fair values. Shared National Credits (SNC) were recorded at quoted sales prices where available. The fair value of the remaining loans was estimated using cash flow projections based on the remaining maturity and repricing terms, adjusted for estimated future credit losses and prepayments and discounted to present value using a risk-adjusted market rate for similar loans. The fair value of collateral dependent loans acquired with deteriorated credit quality was estimated based on the Company's analysis of the fair value of each loan's underlying collateral, discounted using market-derived rates of return with consideration given to the period of time and costs associated with foreclosure and disposition of the collateral. (3) Adjustment to remove the Cascade allowance for loan losses at acquisition date, as the credit risk is accounted for in the fair value adjustment for loans receivable described in (2) above. (4) Write up of the book value of premises and equipment to their estimated fair values on the date of acquisition based upon appraisals obtained from an independent third party appraiser or broker's opinion of value. (5) Adjustment represents the value of the core deposit base assumed in the acquisition based upon valuation from an independent accounting and advisory firm. (6) Adjustment consists of the write-off of pre-existing deferred tax assets as a result of the acquisition. (7) Adjustment consists of various other assets recorded as a result of the acquisition, including mortgage servicing rights, SBA servicing rights, and favorable leases offset by reductions to the fair value of other items. (8) Decrease in book value of time deposits to their estimated fair values based upon interest rates of similar time deposits with similar terms on the date of acquisition based upon valuation from an independent accounting and advisory firm. (9) Increase in fair value due to credit card incentive program, unfavorable leases, write-off of balance sheet reserve, and swap liability offset. The core deposit intangible asset of $48.0 million is being amortized using an accelerated method over the estimated useful lives of the related deposits of ten years. In accordance with Accounting Standards Codification ("ASC") Topic 805-740 "Business Combinations - Income Taxes," the Company reviewed its valuation allowance for deferred tax assets as a result of the Cascade acquisition. As part of evaluating whether or not the acquired deferred tax assets were realizable, the Company wrote-off state and local net operating losses to the balance that the Company determined would be realizable in future periods. The valuation allowance from Bank of the Cascades at the date of the acquisition related entirely to state and local net operating losses. As such, the Company reduced its valuation allowance for deferred tax assets to $ 0 . The Company recorded $13.0 million and $23.9 million in pre-tax acquisition related expenses for the three and nine months ended September 30, 2017, respectively, including professional and legal fees of $0 and $6.5 million , respectively, to directly consummate the merger. These costs are incorporated in non-interest expenses in the Company’s consolidated statements of income and are summarized below. Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 Legal and Professional Fees $ 2,498 $ 8,995 Employee Expenses 1,755 5,041 Technology Conversion and Contract Termination 7,090 7,779 Other 1,673 2,039 Total Acquisition Related Expenses $ 13,016 $ 23,854 The Company acquired certain loans that are subject to Accounting Standards Codification ("ASC") Topic 310-30 "Loans and Debt Securities Acquired with Deteriorated Credit Quality." ASC Topic 310-30 provides recognition, measurement and disclosure guidance for acquired loans that have evidence of deterioration in credit quality since origination for which it is probable, at acquisition, the Company will be unable to collect all contractual amounts owed. For loans that meet the criteria stipulated in ASC Topic 310-30, the excess of all cash flows expected at acquisition over the initial fair value of the loans acquired ("accretable yield") is amortized to interest income over the expected remaining lives of the underlying loans using the effective interest method. The accretable yield will fluctuate due to changes in (i) estimated lives of underling credit-impaired loans, (ii) assumptions regarding future principal and interest amounts collected, and (iii) indices used to fair value variable rate loans. Information regarding acquired credit-impaired loans as of the May 30, 2017 acquisition date is as follows: Contractually required principal and interest payments $ 48,041 Contractual cash flows not expected to be collected ("non-accretable discount") 23,376 Cash flows expected to be collected 24,665 Interest component of cash flows expected to be collected ("accretable discount") 1,901 Fair value of acquired credit-impaired loans $ 22,764 Information regarding acquired loans not deemed credit-impaired at the acquisition date is as follows: Contractually required principal and interest payments $ 2,098,452 Contractual cash flows not expected to be collected due to projected prepayment 23,387 Fair value at acquisition $ 2,067,869 The accompanying consolidated statements of income include the results of operations of the acquired entity from the May 30, 2017 acquisition date. For the period from May 30, 2017 to June 30, 2017, Cascade reported revenues of $ 12.9 million and net income of $ 3.0 million. The acquired entity continued to operate as Bank of the Cascades until August 11, 2017 at which point the operations were integrated with the Company's operations, and Bank of the Cascades merged with First Interstate Bank. Standalone amounts for the Bank of the Cascades were no longer available after that date. The following table presents unaudited supplemental pro forma consolidated revenues and net income as if the acquisition had occurred as of January 1, 2016. Three months ended September 30, Nine months ended September 30, 2017 2016 2017 2016 Interest income $ 108,765 $ 99,288 $ 312,091 $ 289,060 Non-interest income 38,274 39,811 116,171 114,881 Total revenues $ 147,039 $ 139,099 $ 428,262 $ 403,941 Net income $ 34,903 $ 28,769 $ 94,017 $ 44,317 EPS - basic $ 0.52 $ 0.52 $ 1.55 $ 0.79 EPS - diluted 0.51 0.51 1.53 0.79 The unaudited supplemental pro forma net income presented in the table above for 2017 was adjusted to exclude acquisition-related costs, including change in control expenses related to employee benefit plans and legal and professional expenses of $ 19.7 million, net of tax. Pro forma net income presented in the table above for 2016 was adjusted to include the aforementioned acquisition-related costs. The unaudited supplemental pro forma net income presented in the table above for 2017 and 2016 includes adjustments for scheduled amortization of core deposit intangible assets acquired in the acquisition. The unaudited supplemental pro forma net income presented in the table above for 2017 and 2016 does not capture operating costs savings and other business synergies expected as a result of the acquisition.

Goodwill and Intangibles

Goodwill and Intangibles	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	Goodwill and Intangibles The Company recorded $232.2 million of provisional goodwill in connection with the Cascade merger. In accordance with the Intangibles - Goodwill and Other topic of the Financial Accounting Standards Board (“FASB”) ASC 350, goodwill is not amortized but is reviewed for potential impairment at the reporting unit level. Management analyzes its goodwill for impairment on an annual basis and between annual tests in certain circumstances, such as upon material adverse changes in legal, business, regulatory and economic factors. An impairment loss is recorded to the extent that the carrying amount of goodwill exceeds its implied fair value. The Company performed an impairment assessment as of July 1, 2017 and 2016 and concluded that there was no impairment to goodwill. Core deposit intangibles (“CDI”) are evaluated for impairment if events and circumstances indicate a possible impairment. The CDI are amortized using an accelerated method based on the estimated weighted average useful lives of the related deposits, which is ten years. The following table sets forth activity for CDI for the three and nine months ended September 30, 2017 and 2016: Three months ended Nine months ended September 30, September 30, 2017 2016 2017 2016 CDI, net, beginning of period $ 52,837 $ 8,935 $ 9,648 $ 10,589 Established through acquisitions or provisional adjustments 19 2,486 47,968 2,486 Reductions due to sale of accounts — — (3,068 ) — CDI current period amortization (1,885 ) (875 ) (3,577 ) (2,529 ) Total CDI, net, at September 30 $ 50,971 $ 10,546 $ 50,971 $ 10,546 Subsequent to the acquisition of Cascade, the Company sold the custodial rights to the all of its Health Savings Account (HSA) portfolio, including HSA acquired from Cascade. The Company recognized no gain or loss on the sale of the acquired HSA as the excess of consideration received over HSA book value was recorded as reduction to CDI at the acquisition of Cascade. The following table provides the estimated future CDI amortization expense: Years Ending December 31, 2017 remaining $ 1,298 2018 5,093 2019 4,994 2020 4,872 2021 4,729 Thereafter 29,985

Investment Securities

Investment Securities	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities The amortized cost and approximate fair values of investment securities are summarized as follows: September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Available-for-Sale: U.S. Treasury notes $ 3,206 $ 1 $ (2 ) $ 3,205 Obligations of U.S. government agencies 508,449 338 (3,209 ) 505,578 U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 1,431,125 8,829 (4,716 ) 1,435,238 Private mortgage-backed securities 97,715 313 (190 ) 97,838 Corporate securities 66,754 126 (2 ) 66,878 Other investments 2,951 9 — 2,960 Total $ 2,110,200 $ 9,616 $ (8,119 ) $ 2,111,697 September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Held-to-Maturity: State, county and municipal securities $ 180,981 $ 3,726 $ (123 ) $ 184,584 U.S agency residential mortgage-backed securities & 243,380 10,725 (10,172 ) 243,933 Obligations of U.S. government agencies 19,737 43 (19 ) 19,761 Corporate securities 61,704 272 (33 ) 61,943 Other investments 183 1 — 184 Total $ 505,985 $ 14,767 $ (10,347 ) $ 510,405 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Available-for-Sale: U.S. Treasury notes $ 3,608 $ 5 $ (1 ) $ 3,612 Obligations of U.S. government agencies 397,411 343 (6,457 ) 391,297 U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 1,220,890 6,412 (13,601 ) 1,213,701 Private mortgage-backed securities 116 1 (1 ) 116 Other investments 2,951 21 — 2,972 Total $ 1,624,976 $ 6,782 $ (20,060 ) $ 1,611,698 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Held-to-Maturity: State, county and municipal securities $ 160,192 $ 2,723 $ (542 ) $ 162,373 Obligations of U.S. government agencies 19,737 — (162 ) 19,575 U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 279,578 7,804 (9,249 ) 278,133 Corporate securities 53,032 139 (211 ) 52,960 Other investments 231 1 — 232 Total $ 512,770 $ 10,667 $ (10,164 ) $ 513,273 Gross realized gains and losses from the disposition of investment securities are summarized in the following table: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Gross realized gains $ 1,072 $ 239 $ 1,079 $ 404 Gross realized losses (301 ) (14 ) (301 ) (92 ) The following tables show the gross unrealized losses and fair values of investment securities, aggregated by investment category, and the length of time individual investment securities have been in a continuous unrealized loss position, as of September 30, 2017 and December 31, 2016 : Less than 12 Months 12 Months or More Total September 30, 2017 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Available-for-Sale: U.S. Treasury notes $ 2,201 $ (2 ) $ — $ — $ 2,201 $ (2 ) Obligations of U.S. government agencies 303,060 (2,458 ) 86,718 (751 ) 389,778 (3,209 ) U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 556,771 (3,731 ) 74,732 (985 ) 631,503 (4,716 ) Private mortgage-backed securities 30,518 (189 ) 31 (1 ) 30,549 (190 ) Corporate securities 6,987 (2 ) — — 6,987 (2 ) Total $ 899,537 $ (6,382 ) $ 161,481 $ (1,737 ) $ 1,061,018 $ (8,119 ) Less than 12 Months 12 Months or More Total September 30, 2017 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Held-to-Maturity: State, county and municipal securities $ 25,207 $ (97 ) $ 4,208 $ (26 ) $ 29,415 $ (123 ) U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 38,712 (8,814 ) 18,846 (1,358 ) 57,558 (10,172 ) Obligations of U.S. government agencies 9,972 (19 ) — — 9,972 (19 ) Corporate securities 3,966 — 5,017 (33 ) 8,983 (33 ) Total $ 77,857 $ (8,930 ) $ 28,071 $ (1,417 ) $ 105,928 $ (10,347 ) Less than 12 Months 12 Months or More Total December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Available-for-Sale: U.S. Treasury notes $ 598 $ (1 ) $ — $ — $ 598 $ (1 ) Obligations of U.S. government agencies 316,511 (6,457 ) — — 316,511 (6,457 ) U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 746,265 (13,102 ) 15,801 (499 ) 762,066 (13,601 ) Private mortgage-backed securities — — 48 (1 ) 48 (1 ) Total $ 1,063,374 $ (19,560 ) $ 15,849 $ (500 ) $ 1,079,223 $ (20,060 ) Less than 12 Months 12 Months or More Total December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Held-to-Maturity: State, county and municipal securities $ 42,518 $ (533 ) $ 2,831 $ (9 ) $ 45,349 $ (542 ) Obligations of U.S. government agencies 19,575 (162 ) — — 19,575 (162 ) U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 108,857 (7,973 ) 19,986 (1,276 ) 128,843 (9,249 ) Corporate securities 32,474 (211 ) — — 32,474 (211 ) Total $ 203,424 $ (8,879 ) $ 22,817 $ (1,285 ) $ 226,241 $ (10,164 ) The investment portfolio is evaluated quarterly for other-than-temporary declines in the market value of each individual investment security. The Company had 358 and 396 individual investment securities that were in an unrealized loss position as of September 30, 2017 and December 31, 2016 , respectively. As of September 30, 2017 , the Company had the intent and ability to hold these investment securities for a period of time sufficient to allow for an anticipated recovery. Furthermore, the Company does not have the intent to sell any of the available-for-sale securities in the above table and it is more likely than not that the Company will not have to sell any securities before a recovery in cost. No impairment losses were recorded during three or nine months ended September 30, 2017 or 2016 . Maturities of investment securities at September 30, 2017 are shown below. Maturities of mortgage-backed securities have been adjusted to reflect shorter maturities based upon estimated prepayments of principal. All other investment securities maturities are shown at contractual maturity dates. Available-for-Sale Held-to-Maturity September 30, 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Within one year $ 375,199 $ 376,264 $ 87,077 $ 83,899 After one year but within five years 1,287,854 1,288,384 264,417 272,442 After five years but within ten years 278,782 278,277 119,579 121,039 After ten years 168,365 168,772 34,912 33,025 Total $ 2,110,200 $ 2,111,697 $ 505,985 $ 510,405 As of September 30, 2017 , the Company had investment securities callable within one year with amortized costs and estimated fair values of $ 94,461 and $ 94,348 , respectively. These investment securities are primarily included in the after one year but within five years category in the table above. As of September 30, 2017 , the Company did not have any callable structured notes.

Loans

Loans	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Loans	Loans The following tables present the Company's recorded investment and contractual aging of the Company's recorded investment in loans by class as of the dates indicated. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Total Loans 30 - 59 60 - 89 > 90 30 or More Days Days Days Days Current Non-accrual Total As of September 30, 2017 Past Due Past Due Past Due Past Due Loans Loans Loans Real estate Commercial $ 4,582 $ 1,160 $ 2,502 $ 8,244 $ 2,722,265 $ 28,042 $ 2,758,551 Construction: Land acquisition & development 1,656 493 65 2,214 345,234 4,720 352,168 Residential 1,245 1,598 470 3,313 230,533 205 234,051 Commercial — — — — 113,173 3,844 117,017 Total construction loans 2,901 2,091 535 5,527 688,940 8,769 703,236 Residential 8,502 6,313 187 15,002 1,478,314 5,711 1,499,027 Agricultural 1,327 8,533 — 9,860 148,219 2,218 160,297 Total real estate loans 17,312 18,097 3,224 38,633 5,037,738 44,740 5,121,111 Consumer: Indirect consumer 6,840 1,659 347 8,846 778,434 1,505 788,785 Other consumer 1,391 498 68 1,957 175,275 358 177,590 Credit card 1,043 408 671 2,122 70,087 — 72,209 Total consumer loans 9,274 2,565 1,086 12,925 1,023,796 1,863 1,038,584 Commercial 3,308 1,094 1,077 5,479 1,154,196 26,532 1,186,207 Agricultural 1,769 97 278 2,144 149,192 1,345 152,681 Other, including overdrafts — — — — 3,804 — 3,804 Loans held for investment 31,663 21,853 5,665 59,181 7,368,726 74,480 7,502,387 Mortgage loans originated for sale — — — — 49,729 — 49,729 Total loans $ 31,663 $ 21,853 $ 5,665 $ 59,181 $ 7,418,455 $ 74,480 $ 7,552,116 Total Loans 30 - 59 60 - 89 > 90 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2016 Past Due Past Due Past Due Past Due Loans Loans Loans Real estate Commercial $ 7,307 $ 1,099 $ 303 $ 8,709 $ 1,799,525 $ 26,211 $ 1,834,445 Construction: Land acquisition & development 633 352 279 1,264 202,223 5,025 208,512 Residential 931 264 — 1,195 146,245 456 147,896 Commercial — — — — 124,827 762 125,589 Total construction loans 1,564 616 279 2,459 473,295 6,243 481,997 Residential 3,986 1,280 702 5,968 1,014,990 6,435 1,027,393 Agricultural 341 287 — 628 165,293 4,327 170,248 Total real estate loans 13,198 3,282 1,284 17,764 3,453,103 43,216 3,514,083 Consumer: Indirect consumer 8,425 2,329 712 11,466 740,163 780 752,409 Other consumer 1,322 235 167 1,724 146,006 357 148,087 Credit card 504 333 567 1,404 68,366 — 69,770 Total consumer loans 10,251 2,897 1,446 14,594 954,535 1,137 970,266 Commercial 3,171 727 734 4,632 767,878 25,432 797,942 Agricultural 1,518 362 14 1,894 127,956 3,008 132,858 Other, including overdrafts — 1 311 312 1,289 — 1,601 Loans held for investment 28,138 7,269 3,789 39,196 5,304,761 72,793 5,416,750 Mortgage loans originated for sale — — — — 61,794 — 61,794 Total loans $ 28,138 $ 7,269 $ 3,789 $ 39,196 $ 5,366,555 $ 72,793 $ 5,478,544 Loans from business combinations included in the tables above include certain loans that had evidence of deterioration in credit quality since origination and for which it was probable, at acquisition, that all contractually required payments would not be collected. The following table displays the outstanding unpaid balances and accrual status of loans acquired with credit impairment as of September 30, 2017 and 2016 : As of September 30, 2017 2016 Outstanding balance $ 46,199 $ 38,505 Carrying value Loans on accrual status 30,804 23,665 Total carrying value $ 30,804 $ 23,665 The following table summarizes changes in the accretable yield for loans acquired credit impaired for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Beginning balance $ 7,650 $ 5,905 $ 6,803 $ 6,713 Additions 167 1,114 2,096 1,114 Accretion income (858 ) (670 ) (2,131 ) (1,899 ) Reductions due to exit events (143 ) (595 ) (1,131 ) (900 ) Reclassifications from nonaccretable differences 498 729 1,677 1,455 Ending balance $ 7,314 $ 6,483 $ 7,314 $ 6,483 Acquired loans that met the criteria for nonaccrual of interest prior to acquisition were considered performing upon acquisition. If interest on non-accrual loans had been accrued, such income would have been approximately $ 946 and $ 820 for the three months ended September 30, 2017 and 2016 , respectively, and approximately $1,814 and $2,492 for the nine months ended September 30, 2017 , and 2016, respectively. The Company considers impaired loans to include all originated loans, except consumer loans, that are risk rated as doubtful, or have been placed on non-accrual status or renegotiated in troubled debt restructurings, and all loans acquired with evidence of deterioration in credit quality and for which it was probable, at acquisition, that the Company would be unable to collect all contractual amounts owed. The following tables present information on the Company’s recorded investment in impaired loans as of dates indicated: As of September 30, 2017 Unpaid Total Principal Balance Recorded Investment With No Allowance Recorded Investment With Allowance Total Recorded Investment Related Allowance Real estate: Commercial $ 47,934 $ 21,558 $ 16,035 $ 37,593 $ 3,947 Construction: Land acquisition & development 11,290 3,694 1,714 5,408 711 Residential 310 205 — 205 — Commercial 4,725 417 3,537 3,954 2,148 Total construction loans 16,325 4,316 5,251 9,567 2,859 Residential 8,990 5,629 2,122 7,751 218 Agricultural 2,681 2,425 156 2,581 4 Total real estate loans 75,930 33,928 23,564 57,492 7,028 Consumer 27 — 25 25 14 Commercial 36,787 14,623 16,748 31,371 6,426 Agricultural 1,585 951 609 1,560 435 Total $ 114,329 $ 49,502 $ 40,946 $ 90,448 $ 13,903 As of December 31, 2016 Unpaid Total Principal Balance Recorded Investment With No Allowance Recorded Investment With Allowance Total Recorded Investment Related Allowance Real estate: Commercial $ 57,017 $ 24,410 $ 21,420 $ 45,830 $ 2,847 Construction: Land acquisition & development 12,084 4,330 1,813 6,143 826 Residential 1,555 219 619 838 1 Commercial 4,786 3,940 647 4,587 657 Total construction loans 18,425 8,489 3,079 11,568 1,484 Residential 8,222 4,074 2,470 6,544 253 Agricultural 5,069 4,509 181 4,690 4 Total real estate loans 88,733 41,482 27,150 68,632 4,588 Commercial 40,314 13,230 19,167 32,397 9,254 Agricultural 3,738 3,280 382 3,662 112 Total $ 132,785 $ 57,992 $ 46,699 $ 104,691 $ 13,954 The following table presents the average recorded investment in and income recognized on impaired loans for the periods indicated: Three Months Ended September 30, 2017 2016 Average Recorded Investment Income Recognized Average Recorded Investment Income Recognized Real estate: Commercial $ 40,362 $ 54 $ 33,408 $ 100 Construction: Land acquisition & development 5,383 2 6,797 13 Residential 207 — 274 — Commercial 4,192 1 1,055 1 Total construction loans 9,782 3 8,126 14 Residential 7,123 4 3,282 4 Agricultural 2,642 — 4,786 2 Total real estate loans 59,909 61 49,602 120 Consumer 25 — — Commercial 31,637 47 30,123 72 Agricultural 2,270 — 2,249 — Total $ 93,841 $ 108 $ 81,974 $ 192 Nine Months Ended September 30, 2017 2016 Average Recorded Investment Income Recognized Average Recorded Investment Income Recognized Real estate: Commercial $ 41,712 $ 281 $ 35,572 $ 241 Construction: Land acquisition & development 5,776 10 6,992 32 Residential 522 — 279 — Commercial 4,271 45 1,007 3 Total construction loans 10,569 55 8,278 35 Residential 7,148 12 4,219 7 Agricultural 3,636 — 4,607 3 Total real estate loans 63,065 348 52,676 286 Consumer 13 — — — Commercial 31,884 156 27,781 128 Agricultural 2,611 2 2,341 — Total $ 97,573 $ 506 $ 82,798 $ 414 The amount of interest income recognized by the Company within the period that the loans were impaired was primarily related to loans modified in a troubled debt restructuring that remained on accrual status. Interest payments received on non-accrual impaired loans are applied to principal. Interest income is subsequently recognized only to the extent cash payments are received in excess of principal due. If interest on impaired loans had been accrued, interest income on impaired loans would have been approximately $ 946 and $ 993 for the three months ended September 30, 2017 and 2016 , respectively, and approximately $1,814 and $2,994 for the nine months ended September 30, 2017 and 2016, respectively. Collateralized impaired loans are generally recorded at the fair value of the underlying collateral using discounted cash flows, independent appraisals and management estimates based upon current market conditions. For loans measured under the present value of cash flows method, the change in present value attributable to the passage of time, if applicable, is recognized in the provision for loan losses and thus no interest income is recognized. Modifications of performing loans are made in the ordinary course of business and are completed on a case-by-case basis as negotiated with the borrower. Loan modifications typically include interest rate changes, interest only periods of less than twelve months, short-term payment deferrals and extension of amortization periods to provide payment relief. A loan modification is considered a troubled debt restructuring if the borrower is experiencing financial difficulties and the Company, for economic or legal reasons, grants a concession to the borrower that it would not otherwise consider. Certain troubled debt restructurings are on non-accrual status at the time of restructuring and may be returned to accrual status after considering the borrower's sustained repayment performance in accordance with the restructuring agreement for a period of at least six months and management is reasonably assured of future performance. If the troubled debt restructuring meets these performance criteria and the interest rate granted at the modification is equal to or greater than the rate that the Company was willing to accept at the time of the restructuring for a new loan with comparable risk, then the loan will return to performing status and the accrual of interest will resume, although they continue to be individually evaluated for impairment and disclosed as impaired loans. The Company had loans renegotiated in troubled debt restructurings of $ 45,859 as of September 30, 2017 , of which $ 34,997 were included in non-accrual loans and $ 10,862 were on accrual status. The Company had loans renegotiated in troubled debt restructurings of $ 49,652 as of December 31, 2016 , of which $ 27,309 were included in non-accrual loans and $ 22,343 were on accrual status. The following table presents information on the Company's troubled debt restructurings that occurred during the three and nine months ended September 30, 2017 : Number of Notes Type of Concession Principal Balance at Restructure Date Three Months Ended September 30, 2017 Interest only period Extension of term or amortization schedule Interest rate adjustment Other (1) Commercial 1 — — — 611 611 Total loans restructured during period 1 $ — $ — $ — $ 611 $ 611 (1) Other includes concessions that reduce or defer payments for a specified period of time and/or concessions that do not fit into other designated categories. Number of Notes Type of Concession Principal Balance at Restructure Date Nine Months Ended September 30, 2017 Interest only period Extension of terms or maturity Interest rate adjustment Other (1) Commercial real estate 5 $ 1,475 $ 388 $ — $ 909 $ 2,772 Commercial 16 511 1,968 — 6,057 8,536 Total loans restructured during period 21 $ 1,986 $ 2,356 $ — $ 6,966 $ 11,308 (1) Other includes concessions that reduce or defer payments for a specified period of time and/or do not fit into other designated categories. For troubled debt restructurings that were on non-accrual status or otherwise deemed impaired before the modification, a specific reserve may already be recorded. In periods subsequent to modification, the Company continues to evaluate all troubled debt restructurings for possible impairment and recognizes impairment through the allowance. Additionally these loans continue to work their way through the credit cycle through charge-off, pay-off or foreclosure. Financial effects of modifications of troubled debt restructurings may include principal loan forgiveness or other charge-offs directly related to the restructuring. The Company had no charge-offs directly related to modifying troubled debt restructurings during the three or nine months ended September 30, 2017 or 2016 . The following table presents information on the Company's troubled debt restructurings during the previous 12 months for which there was a payment default during the three and nine months ended September 30, 2017 . The Company considers a payment default to occur on troubled debt restructurings when the loan is 90 days or more past due or was placed on non-accrual status after the modification. Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 Number of Notes Balance Number of Notes Balance Commercial real estate 1 $ 177 2 $ 2,407 Commercial construction — — 1 3,528 Commercial 1 1,300 1 1,300 Total 2 $ 1,477 4 $ 7,235 At September 30, 2017 , there were no material commitments to lend additional funds to borrowers whose existing loans have been renegotiated or are classified as non-accrual. As part of the on-going and continuous monitoring of the credit quality of the Company’s loan portfolio, management tracks internally assigned risk classifications of loans. The Company adheres to a Uniform Classification System developed jointly by the various bank regulatory agencies to internally risk rate loans. The Uniform Classification System defines three broad categories of criticized assets, which the Company uses as credit quality indicators: Other Assets Especially Mentioned — includes loans that exhibit weaknesses in financial condition, loan structure or documentation, which if not promptly corrected, may lead to the development of abnormal risk elements. Substandard — includes loans that are inadequately protected by the current sound worth and paying capacity of the borrower. Although the primary source of repayment for a substandard loan is not currently sufficient, collateral or other sources of repayment are sufficient to satisfy the debt. Continuance of a substandard loan is not warranted unless positive steps are taken to improve the worthiness of the credit. Doubtful — includes loans that exhibit pronounced weaknesses to a point where collection or liquidation in full, on the basis of currently existing facts, conditions and values, is highly questionable and improbable. Doubtful loans are required to be placed on non-accrual status and are assigned specific loss exposure. Company management undertakes the same process for assigning risk ratings to acquired loans as it does for originated loans. Acquired loans rated as substandard or lower or that were on non-accrual status or designated as troubled debt restructurings at the time of acquisition are deemed to be acquired credit impaired loans accounted for under ASC Topic 310-30, regardless of whether they are classified as performing or non-performing loans. The following tables present the Company’s recorded investment in criticized loans by class and credit quality indicator based on the most recent analysis performed as of the dates indicated: As of September 30, 2017 Other Assets Especially Mentioned Substandard Doubtful Total Criticized Loans Real estate: Commercial $ 79,921 $ 107,791 $ 12,025 $ 199,737 Construction: Land acquisition & development 5,425 13,818 1,597 20,840 Residential 3,690 2,201 — 5,891 Commercial 2,564 3,842 3,747 10,153 Total construction loans 11,679 19,861 5,344 36,884 Residential 4,607 11,664 1,039 17,310 Agricultural 1,212 23,574 — 24,786 Total real estate loans 97,419 162,890 18,408 278,717 Consumer: Indirect consumer 660 2,116 120 2,896 Other consumer 458 849 140 1,447 Total consumer loans 1,118 2,965 260 4,343 Commercial 43,365 61,612 16,495 121,472 Agricultural 5,219 11,859 979 18,057 Total $ 147,121 $ 239,326 $ 36,142 $ 422,589 As of December 31, 2016 Other Assets Especially Mentioned Substandard Doubtful Total Criticized Loans Real estate: Commercial $ 85,292 $ 85,293 $ 10,842 $ 181,427 Construction: Land acquisition & development 13,414 6,214 1,401 21,029 Residential 412 1,621 656 2,689 Commercial 1,555 6,344 664 8,563 Total construction loans 15,381 14,179 2,721 32,281 Residential 5,038 12,472 764 18,274 Agricultural 3,831 17,813 — 21,644 Total real estate loans 109,542 129,757 14,327 253,626 Consumer: Indirect consumer 778 1,527 101 2,406 Other consumer 681 1,036 264 1,981 Total consumer loans 1,459 2,563 365 4,387 Commercial 46,402 29,281 21,240 96,923 Agricultural 6,178 10,724 404 17,306 Total $ 163,581 $ 172,325 $ 36,336 $ 372,242 The Company maintains a credit review function, which is independent of the credit approval process, to assess assigned internal risk classifications and monitor compliance with internal lending policies and procedures. Written action plans with firm target dates for resolution of identified problems are maintained and reviewed on a quarterly basis for all categories of criticized loans.

Allowance for Loan Losses

Allowance for Loan Losses	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Allowance for Loan Losses	Allowance for Loan Losses The following tables present a summary of changes in the allowance for loan losses by portfolio segment for the periods indicated: Three Months Ended September 30, 2017 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Beginning balance $ 33,498 $ 7,554 $ 33,124 $ 1,525 $ — $ 75,701 Provision charged to operating expense (690 ) 2,620 1,530 (17 ) — 3,443 Less loans charged-off (1,695 ) (3,115 ) (2,609 ) (41 ) — (7,460 ) Add back recoveries of loans previously charged-off 613 962 1,313 — — 2,888 Ending balance $ 31,726 $ 8,021 $ 33,358 $ 1,467 $ — $ 74,572 Nine Months Ended September 30, 2017 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Beginning balance $ 28,625 $ 7,711 $ 38,092 $ 1,786 $ — $ 76,214 Provision charged to operating expense 4,775 5,157 (2,145 ) (259 ) — 7,528 Less loans charged-off (2,938 ) (8,123 ) (4,450 ) (111 ) — (15,622 ) Add back recoveries of loans previously charged-off 1,264 3,276 1,861 51 — 6,452 Ending balance $ 31,726 $ 8,021 $ 33,358 $ 1,467 $ — $ 74,572 As of September 30, 2017 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Loans individually evaluated for impairment $ 7,028 $ 14 $ 6,426 $ 435 $ — $ 13,903 Loans collectively evaluated for impairment 24,698 8,007 26,932 1,032 — 60,669 Allowance for loan losses $ 31,726 $ 8,021 $ 33,358 $ 1,467 $ — $ 74,572 Loans held for investment: Individually evaluated for impairment $ 57,492 $ 25 $ 31,371 $ 1,560 $ — $ 90,448 Collectively evaluated for impairment 5,063,619 1,038,559 1,154,836 151,121 3,804 7,411,939 Total loans $ 5,121,111 $ 1,038,584 $ 1,186,207 $ 152,681 $ 3,804 $ 7,502,387 Three Months Ended September 30, 2016 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Beginning balance $ 32,281 $ 6,315 $ 39,995 $ 1,749 $ — $ 80,340 Provision charged to operating expense (352 ) 2,395 265 55 — 2,363 Less loans charged-off (379 ) (2,157 ) (579 ) — — (3,115 ) Add back recoveries of loans previously charged-off 221 742 680 4 — 1,647 Ending balance $ 31,771 $ 7,295 $ 40,361 $ 1,808 $ — $ 81,235 Nine Months Ended September 30, 2016 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Beginning balance $ 52,296 $ 5,144 $ 18,775 $ 602 $ — $ 76,817 Provision charged to operating expense (20,492 ) 5,747 22,268 1,390 — 8,913 Less loans charged-off (2,824 ) (5,761 ) (2,085 ) (188 ) — (10,858 ) Add back recoveries of loans previously charged-off 2,791 2,165 1,403 4 — 6,363 Ending balance $ 31,771 $ 7,295 $ 40,361 $ 1,808 $ — $ 81,235 As of December 31, 2016 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Loans individually evaluated for impairment $ 4,588 $ — $ 9,254 $ 112 $ — $ 13,954 Loans collectively evaluated for impairment 24,037 7,711 28,838 1,674 — 62,260 Allowance for loan losses $ 28,625 $ 7,711 $ 38,092 $ 1,786 $ — $ 76,214 Loans held for investment: Individually evaluated for impairment $ 68,632 $ — $ 32,397 $ 3,662 $ — $ 104,691 Collectively evaluated for impairment 3,445,451 970,266 765,545 129,196 1,601 5,312,059 Total loans $ 3,514,083 $ 970,266 $ 797,942 $ 132,858 $ 1,601 $ 5,416,750 The Company performs a quarterly assessment of the adequacy of its allowance for loan losses in accordance with generally accepted accounting principles. The methodology used to assess the adequacy is consistently applied to the Company's loan portfolio and consists of three elements: (1) specific valuation allowances based on probable losses on impaired loans; (2) historical valuation allowances based on loan loss experience for similar loans with similar characteristics and trends; and (3) general valuation allowances determined based on changes in the nature of the loan portfolio, overall portfolio quality, industry concentrations, delinquency trends, general economic conditions and other qualitative risk factors both internal and external to the Company. Specific allowances are established for loans where management has determined that probability of a loss exists by analyzing the borrower’s ability to repay amounts owed, collateral deficiencies and any relevant qualitative or economic factors impacting the loan. Historical valuation allowances are determined by applying percentage loss factors to the credit exposures from outstanding loans. For commercial, agricultural and real estate loans, loss factors are applied based on the internal risk classifications of these loans. For consumer loans, loss factors are applied on a portfolio basis. For commercial, agriculture and real estate loans, loss factor percentages are based on a migration analysis of our historical loss experience, designed to account for credit deterioration. For consumer loans, loss factor percentages are based on a one-year loss history. General valuation allowances are determined by evaluating, on a quarterly basis, changes in the nature and volume of the loan portfolio, overall portfolio quality, industry concentrations, current economic and regulatory conditions and the estimated impact of these factors on historical loss rates. An allowance for loan losses is established for loans acquired credit impaired and for which the Company projects a decrease in the expected cash flows in periods subsequent to the acquisition of such loans. As of September 30, 2017 and December 31, 2016 , the Company's allowance for loan losses included $727 and $427 , respectively, related to loans acquired credit impaired.

Other Real Estate Owned

Other Real Estate Owned	9 Months Ended
	Sep. 30, 2017
Repossessed Assets [Abstract]
Other Real Estate Owned	Other Real Estate Owned Information with respect to the Company's other real estate owned follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Beginning balance $ 11,286 $ 7,908 $ 10,019 $ 6,254 OREO acquired through acquisition — 1,120 1,192 1,120 Additions 1,419 1,316 3,182 5,335 Valuation adjustments (238 ) — (294 ) (603 ) Dispositions (2,123 ) (897 ) (3,755 ) (2,659 ) Ending balance $ 10,344 $ 9,447 $ 10,344 $ 9,447 The carrying values of foreclosed residential real estate properties included in other real estate owned were $ 1,083 and $2,282 as of September 30, 2017 and December 31, 2016, respectively. The Company had $481 of consumer mortgage loans collateralized by residential real estate property that were in the process of foreclosure as of September 30, 2017 and $0 as of December 31, 2016.

Derivatives and Hedging Activit

Derivatives and Hedging Activities	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative and Hedging Activities	Derivatives and Hedging Activities For asset and liability management purposes, the Company had entered into an interest rate swap contract to hedge against changes in forecasted cash flows due to interest rate exposures. During the third quarter, the Company terminated the existing interest rate swap contract. The swap agreement was a derivative instrument which converts a portion of the Company’s forecasted variable rate debt to a fixed rate (i.e., cash flow hedge) over the payment term of the interest rate swap. The effective portion of the gain or loss on cash flow hedging instruments was initially reported as a component of other comprehensive income and subsequently reclassified into earnings in the same period during which the transaction affects earnings. The ineffective portion of the gain or loss on derivative instruments, if any, would be recognized in earnings. The Company does not enter into interest rate swap agreements for trading or speculative purposes. The Company also enters into certain interest rate swap contracts that are not designated as hedging instruments. These derivative contracts relate to transactions in which the Company enters into an interest rate swap with a customer while at the same time entering into an offsetting interest rate swap with a third party financial institution. Because the Company acts as an intermediary for the customer, changes in the fair value of the underlying derivative contracts for the most part offset each other and do not significantly impact the Company's results of operations. In the normal course of business, the Company enters into interest rate lock commitments to finance residential mortgage loans that are not designated as accounting hedges. These commitments, which contain fixed expiration dates, offer the borrower an interest rate guarantee provided the loan meets underwriting guidelines and closes within the timeframe established by the Company. Interest rate risk arises on these commitments and subsequently closed loans if interest rates change between the time of the interest rate lock and the delivery of the loan to the investor. Loan commitments related to residential mortgage loans intended to be sold are considered derivatives and are marked to market through earnings. In addition to the effects of the change in market interest rate, the fair value measurement of the derivative also contemplates the expected cash flows to be received from the counterparty from the future sale of the loan. The Company sells residential mortgage loans on either a best efforts or mandatory delivery basis. The Company mitigates the effect of the interest rate risk inherent in providing interest rate lock commitments by entering into forward loan sales contracts. During the interest rate lock commitment period, these forward loan sales contracts are marked to market through earnings and are not designated as accounting hedges. Exclusive of the fair value component associated with the projected cash flows from the loan delivery to the investor, the changes in fair value related to movements in market rates of the interest rate lock commitments and the forward loan sales contracts generally move in opposite directions, and the net impact of changes in these valuations on net income during the loan commitment period is generally inconsequential. When the loan is funded to the borrower, the interest rate lock commitment derivative expires and the Company records a loan held for sale. The forward loan sales contracts act as a hedge against the variability in the market value of mortgage loans held for sale. The changes in measurement of the estimated fair values of the interest rate lock commitments and forward loan sales contracts are included in mortgage banking revenues in the accompanying consolidated statements of income. The notional amounts and estimated fair values of the Company's derivatives are presented in the following table. Fair value estimates are obtained from third parties and are based on pricing models. September 30, 2017 December 31, 2016 Notional Amount Estimated Fair Value Notional Amount Estimated Fair Value Derivative Assets (included in other assets): Non-hedging interest rate derivatives: Interest rate swap contracts $ 327,569 $ 8,764 $ 53,593 $ 1,332 Interest rate lock commitments 78,720 1,627 73,422 1,131 Forward loan sales contracts 104,543 330 126,836 286 Total derivative assets $ 510,832 $ 10,721 $ 253,851 $ 2,749 Derivative Liabilities (included in accounts payable and accrued expenses): Derivatives designated as hedges: Interest rate swap contracts $ — $ — $ 100,000 $ 33 Non-hedging interest rate derivatives: Interest rate swap contracts 327,569 9,099 53,593 1,281 Total derivative liabilities $ 327,569 $ 9,099 $ 153,593 $ 1,314 On September 6, 2017 , the Company paid $1.1 million to terminate an existing interest rate swap contract designated as a cash flow hedge, originally entered into on September 22, 2015 , with a notional amount of $100,000 . Under the terms of the interest rate swap contract, the Company would have paid a fixed interest rate of 1.94% and the counterparty would have paid to the Company a variable interest rate equal to the three-month LIBOR. As the contract was terminated prior to the effective date of September 15, 2017 , no cash was exchanged outside of the termination payment. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in Accumulated Other Comprehensive Income and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. During the three and nine months ended September 30, 2017, the Company did not record any hedge ineffectiveness. Derivative assets and liabilities are recorded at fair value on the balance sheet and do not take into account the effects of master netting arrangements. Master netting arrangements allow the Company to settle all contracts held with a single counterparty on a net basis and to offset net contract position with related collateral where applicable. The following table illustrates the potential effect of the Company's master netting arrangements, by type of financial instrument, on the Company's consolidated balance sheets as of September 30, 2017 and December 31, 2016: September 30, 2017 Gross Amounts Recognized Gross Amounts Offset in the Balance Sheet Net Amounts in the Balance Sheet Financial Instruments Fair Value of Financial Collateral in the Balance Sheet Net Amount Financial Assets Interest rate swap contracts $ 8,764 $ — $ 8,764 $ 1,530 $ — $ 7,234 Mortgage related derivatives 1,957 — 1,957 — — 1,957 Total derivatives 10,721 — 10,721 1,530 — 9,191 Total assets $ 10,721 $ — $ 10,721 $ 1,530 $ — $ 9,191 Financial Liabilities Interest rate swap contracts $ 9,099 $ — $ 9,099 $ 1,530 $ 7,569 $ — Total derivatives 9,099 — 9,099 1,530 7,569 — Repurchase agreements 635,288 — 635,288 — 635,288 — Total liabilities $ 644,387 $ — $ 644,387 $ 1,530 $ 642,857 $ — December 31, 2016 Gross Amounts Recognized Gross Amounts Offset in the Balance Sheet Net Amounts in the Balance Sheet Financial Instruments Fair Value of Financial Collateral in the Balance Sheet Net Amount Financial Assets Interest rate swap contracts $ 1,332 $ — $ 1,332 $ 479 $ — $ 853 Mortgage related derivatives 1,417 — 1,417 — — 1,417 Total derivatives 2,749 — 2,749 479 — 2,270 Total assets $ 2,749 $ — $ 2,749 $ 479 $ — $ 2,270 Financial Liabilities Interest rate swap contracts $ 1,314 $ — $ 1,314 $ 479 $ — $ 835 Total derivatives 1,314 — 1,314 479 — 835 Repurchase agreements 537,556 — 537,556 — 537,556 — Total liabilities $ 538,870 $ — $ 538,870 $ 479 $ 537,556 $ 835 The following table presents the pre-tax gains or losses related to derivative contracts that were recorded in accumulated other comprehensive income and other non-interest income in the Company's statements of income for the periods indicated: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Derivatives designated as hedges: Amount of loss recognized in other comprehensive income (effective portion) $ (658 ) $ 512 $ (1,095 ) $ (2,490 ) Reclassification adjustment for derivatives net (gains) losses included in income 1,128 — 1,128 — Non-hedging interest rate derivatives: Amount of gain (loss) recognized in other non-interest income 24 (3 ) (49 ) (82 ) Amount of net fee income recognized in other non-interest income 162 — 441 245 Amount of net gains recognized in mortgage banking revenues 358 752 539 1,970

Capital Stock

Capital Stock	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Capital Stock	Capital Stock The Company had 33,383,364 shares of Class A common stock and 23,072,524 shares of Class B common stock outstanding as of September 30, 2017 . The Company had 21,613,885 shares of Class A common stock and 23,312,291 shares of Class B common stock outstanding as of December 31, 2016 . On May 30, 2017, the Company issued 11,252,750 shares of its Class A common stock with an aggregate value of $ 385,969 as partial consideration for the acquisition of Cascade Bancorp. In addition, during the nine months ended September 30, 2017 , the Company issued 14,926 shares of its Class A common stock to directors for their annual service on the Company's board of directors. The aggregate value of the shares issued to directors of $ 522 is included in stock-based compensation expense in the accompanying consolidated statements of changes in stockholders' equity. During the nine months ended September 30, 2017 , the Company did not repurchase any shares of its Class A common stock. During the nine months ended September 30, 2016 , the Company repurchased and retired 975,877 shares of its Class A common stock in open market transactions at an aggregate purchase price of $25,525 . All repurchases were made pursuant to stock repurchase programs approved by the Company's Board of Directors. Under the terms of the current stock repurchase program, the Company may repurchase up to an additional 24,123 shares of its Class A common stock. All other stock repurchases during the nine months ended September 30, 2017 and 2016 were redemptions of vested restricted shares tendered in lieu of cash for payment of income tax withholding amounts by participants in the Company's equity compensation plans.

Earnings per Common Share

Earnings per Common Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings per Common Share	Earnings per Common Share Basic earnings per common share is calculated by dividing net income by the weighted average number of common shares outstanding during the period presented, excluding unvested restricted stock. Diluted earnings per share is calculated by dividing net income by the weighted average number of common shares determined for the basic earnings per share computation plus the dilutive effects of stock-based compensation using the treasury stock method. The following table sets forth the computation of basic and diluted earnings per share for the three and nine month periods ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Net income $ 27,259 $ 25,193 $ 72,253 $ 70,871 Weighted average common shares outstanding for basic earnings per share computation 56,094,401 44,415,213 49,514,818 44,505,544 Dilutive effects of stock-based compensation 436,467 390,708 486,064 379,368 Weighted average common shares outstanding for diluted earnings per common share computation 56,530,868 44,805,921 50,000,882 44,884,912 Basic earnings per common share $ 0.49 $ 0.57 $ 1.46 $ 1.59 Diluted earnings per common share $ 0.48 $ 0.56 $ 1.45 $ 1.58 Anti-dilutive unvested time restricted stock — 135 94,210 95,886 The Company had 174,696 and 218,556 shares of unvested restricted stock as of September 30, 2017 and 2016 , respectively, that were not included in the computation of diluted earnings per common share because performance conditions for vesting had not been met.

Regulatory Capital

Regulatory Capital	9 Months Ended
	Sep. 30, 2017
Banking and Thrift [Abstract]
Regulatory Capital	Regulatory Capital On July 2, 2013, the Board of Governors of the Federal Reserve Bank issued a final rule implementing a revised regulatory capital framework for U.S. banks in accordance with the Basel III international accord, ("Basel III"). Basel III includes a more stringent definition of capital and introduces a new common equity tier 1, or CET1, capital requirement, sets forth a comprehensive methodology for calculating risk-weighted assets, introduces a conservation buffer and sets out minimum capital ratios and overall capital adequacy standards. Under Basel III, certain deductions and adjustments to regulatory capital began to phase in starting January 1, 2015 and will be fully implemented on January 1, 2018. The capital conservation buffer required under Basel III began to phase in starting January 1, 2016 and will be fully implemented on January 1, 2019. As of September 30, 2017 and December 31, 2016 , the Company exceeded all capital adequacy requirements to which it is subject. Actual capital amounts and ratios for the Company and its bank subsidiary, as of September 30, 2017 and December 31, 2016 are presented in the following tables: Actual Adequately Capitalized Basel III Phase-In Schedule Adequately Capitalized Basel III Fully Phased-In Well Capitalized (1) Amount Ratio Amount Ratio Amount Ratio Amount Ratio September 30, 2017 Total risk-based capital: Consolidated $ 1,100,588 12.76 % $ 797,584 9.25 % $ 905,365 10.50 % $ 862,253 10.00 % FIB 1,097,287 12.78 793,974 9.25 901,268 10.50 858,350 10.00 Tier 1 risk-based capital: Consolidated 1,026,016 11.90 625,133 7.25 732,915 8.50 689,802 8.00 FIB 1,022,715 11.91 622,304 7.25 729,598 8.50 686,680 8.00 Common equity tier 1 risk-based capital: Consolidated 949,821 11.02 495,795 5.75 603,577 7.00 560,464 6.50 FIB 1,022,715 11.91 493,551 5.75 600,845 7.00 557,928 6.50 Leverage capital ratio: Consolidated 1,026,016 8.71 471,221 4.00 471,221 4.00 589,026 5.00 FIB 1,022,715 8.72 469,107 4.00 469,107 4.00 586,384 5.00 Actual Adequately Capitalized Basel III Phase-In Schedule Adequately Capitalized Basel III Fully Phased-In Well Capitalized (1) Amount Ratio Amount Ratio Amount Ratio Amount Ratio December 31, 2016 Total risk-based capital: Consolidated $ 974,488 15.13 % $ 555,665 8.63 % $ 676,070 10.50 % $ 643,876 10.00 % FIB 841,967 13.13 553,459 8.63 673,386 10.50 641,320 10.00 Tier 1 risk-based capital: Consolidated 894,273 13.89 426,890 6.63 547,295 8.50 $ 515,101 8.00 FIB 765,753 11.94 425,195 6.63 545,122 8.50 513,056 8.00 Common equity tier 1 risk-based capital: Consolidated 814,273 12.65 330,308 5.13 450,713 7.00 $ 418,519 6.50 FIB 765,753 11.94 328,997 5.13 448,924 7.00 416,858 6.50 Leverage capital ratio: Consolidated 894,273 10.11 353,838 4.00 353,838 4.00 $ 442,297 5.00 FIB 765,753 8.69 352,283 4.00 352,283 4.00 440,353 5.00 (1) The ratios for the well capitalized requirement are only applicable to FIB. However, the Company manages its capital position as if the requirement applies to the consolidated entity and has presented the ratios as if they also applied on a consolidated basis.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies In the normal course of business, the Company is involved in various other claims and litigation. In the opinion of management, following consultation with legal counsel, the ultimate liability or disposition thereof of all other claims and litigation is not expected to have a material adverse effect on the consolidated financial condition, results of operations or liquidity of the Company. As of September 6, 2017 , the Company terminated a commitment under a forward starting interest rate swap contract with a notional amount of $100,000 . For additional information about the forward starting interest rate swap contract, see Note 8 - Derivatives and Hedging Activities. As of September 30, 2017 , the Company had commitments under construction contracts of $731 . Residential mortgage loans sold to investors in the secondary market are sold with varying recourse provisions. Essentially all of the loan sales agreements require the repurchase of a mortgage loan by the seller in situations such as breach of representation, warranty or covenant; untimely document delivery; false or misleading statements; failure to obtain certain certificates or insurance; unmarketability; etc. Certain loan sales agreements contain repurchase requirements based on payment-related defects that are defined in terms of the number of days or months since the purchase, the sequence number of the payment, and/or the number of days of payment delinquency. Based on the specific terms stated in the agreements, the Company had $ 875 of sold residential mortgage loans with recourse provisions still in effect as of September 30, 2017 .

Financial Instruments with Off-

Financial Instruments with Off-Balance Sheet Risk	9 Months Ended
	Sep. 30, 2017
Financial Instruments with Off-Balance Sheet Risk [Abstract]
Financial Instruments with Off-Balance Sheet Risk	Financial Instruments with Off-Balance Sheet Risk The Company is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit and standby letters of credit. Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the commitment contract. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. At September 30, 2017 , commitments to extend credit to existing and new borrowers approximated $2.1 billion , which included $618.1 million on unused credit card lines and $721.7 million with commitment maturities beyond one year. Standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. At September 30, 2017 , the Company had outstanding standby letters of credit of $52.6 million . The estimated fair value of the obligation undertaken by the Company in issuing the standby letters of credit is included in other liabilities in the Company’s consolidated balance sheet.

Other Comprehensive Income_Loss

Other Comprehensive Income/Loss	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Other Comprehensive Income/Loss	Other Comprehensive Income/Loss The gross amounts of each component of other comprehensive income and the related tax effects are as follows: Pre-tax Tax Expense (Benefit) Net of Tax Three Months Ended September 30, 2017 2016 2017 2016 2017 2016 Investment securities available-for sale: Change in net unrealized gains during period $ (1,812 ) $ (3,430 ) $ (845 ) $ (1,359 ) $ (967 ) $ (2,071 ) Reclassification adjustment for net gains included in net income (771 ) (225 ) (360 ) (89 ) (411 ) (136 ) Change in unamortized loss on available- for-sale securities transferred into held-to- maturity 465 490 217 209 248 281 Unrealized (gain) loss on derivatives (658 ) 512 (307 ) 195 (351 ) 317 Reclassification adjustment for derivatives net (gains) losses included in income 1,128 — 526 — 602 — Defined benefits post-retirement benefit plan: Change in net actuarial (gain) loss (176 ) 15 (82 ) 6 (94 ) 9 Total other comprehensive income $ (1,824 ) $ (2,638 ) $ (851 ) $ (1,038 ) $ (973 ) $ (1,600 ) Pre-tax Tax Expense (Benefit) Net of Tax Nine Months Ended September 30, 2017 2016 2017 2016 2017 2016 Investment securities available-for sale: Change in net unrealized gains during period $ 15,553 $ 15,241 $ 6,135 $ 5,963 $ 9,418 $ 9,278 Reclassification adjustment for net gains included in net income (778 ) (312 ) (307 ) (123 ) (471 ) (189 ) Change in unamortized loss on available- for-sale securities transferred into held-to- maturity 1,394 1,394 550 549 844 845 Unrealized loss on derivatives (1,095 ) (2,490 ) (432 ) (946 ) (663 ) (1,544 ) Reclassification adjustment for derivatives net (gains) losses included in income 1,128 — 445 — 683 — Defined benefits post-retirement benefit plan: Change in net actuarial loss (1,090 ) 43 (430 ) 17 (660 ) 26 Total other comprehensive income $ 15,112 $ 13,876 $ 5,961 $ 5,460 $ 9,151 $ 8,416 The components of accumulated other comprehensive loss, net of related tax effects, are as follows: September 30, December 31, Net unrealized gain (loss) on investment securities available-for-sale $ (353 ) $ (10,143 ) Net unrealized gain (loss) on derivatives — (23 ) Net actuarial gain (loss) on defined benefit post-retirement benefit plans 1,376 2,038 Net accumulated other comprehensive gain (loss) $ 1,023 $ (8,128 )

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. There is a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The three levels of inputs that may be used to measure fair value are as follows: • Level 1 - Quoted prices in active markets for identical assets or liabilities • Level 2 - Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities • Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of assets or liabilities The methodologies used by the Company in determining the fair values of each class of financial instruments are based primarily on the use of independent, market-based data to reflect a value that would be reasonably expected in an orderly transaction between market participants at the measurement date, and therefore are classified within Level 2 of the valuation hierarchy. There were no transfers between fair value hierarchy levels during the three and nine months ended September 30, 2017 and 2016 . Further details on the methods used to estimate the fair value of each class of financial instruments above are discussed below: Investment Securities Available-for-Sale . The Company obtains fair value measurements for investment securities from an independent pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the investment's terms and conditions, among other things. Vendors chosen by the Company are widely recognized vendors whose evaluations support the pricing functions of financial institutions, investment and mutual funds, and portfolio managers. If needed, a broker may be utilized to determine the reported fair value of investment securities. Loans Held for Sale. Fair value measurements for loans held for sale are obtained from an independent pricing service. The fair value measurements consider observable data that may include binding contracts or quotes or bids from third party investors as well as loan level pricing adjustments. Interest Rate Swap Contracts. Fair values for derivative interest rate swap contracts are based upon the estimated amounts to settle the contracts considering current interest rates and are calculated using discounted cash flows that are observable or that can be corroborated by observable market data. The inputs used to determine fair value include the 3 month LIBOR forward curve to estimate variable rate cash inflows and the federal funds effective swap rate to estimate the discount rate. The estimated variable rate cash inflows are compared to the fixed rate outflows and such difference is discounted to a present value to estimate the fair value of the interest rate swaps. The change in the value of derivative assets attributable to basis risk, or the risk that offsetting investments in a hedging strategy will not experience price changes in entirely opposite directions from each other, was not significant in the reported periods. The Company also obtains and compares the reasonableness of the pricing from an independent third party. Interest Rate Lock Commitments. Fair value measurements for interest rate lock commitments are obtained from an independent pricing service. The fair value measurements consider observable data that may include prices available from secondary market investors taking into consideration various characteristics of the loan, including the loan amount, interest rate, value of the servicing and loan to value ratio, among other things. Observable data is then adjusted to reflect changes in interest rates, the Company's estimated pull-through rate and estimated direct costs necessary to complete the commitment into a closed loan net of origination and processing fees collected from the borrower. Forward Loan Sales Contracts. The fair value measurements for forward loan sales contracts are obtained from an independent pricing service. The fair value measurements consider observable data that includes sales of similar loans. Deferred Compensation Plan Assets and Liabilities. The fair values of deferred compensation plan assets are based primarily on the use of independent, market-based data to reflect a value that would be reasonably expected in an orderly transaction between market participants at the measurement date. These investments are in the same funds and purchased in the same amounts as the participants’ selected investments, which represent the underlying liabilities to plan participants. Deferred compensation plan liabilities are recorded at amounts due to participants, based on the fair value of participants’ selected investments. Financial assets and financial liabilities measured at fair value on a recurring basis are as follows: Fair Value Measurements at Reporting Date Using As of September 30, 2017 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment securities available-for-sale: U.S. Treasury Notes $ 3,205 $ — $ 3,205 $ — Obligations of U.S. government agencies 505,578 — 505,578 — U.S. agencies mortgage-backed securities & collateralized mortgage obligations 1,435,238 — 1,435,238 — Private mortgage-backed securities 97,838 — 97,838 — Corporate securities 66,878 — 66,878 Other investments 2,960 — 2,960 — Loans held for sale 49,729 — 49,729 — Derivative assets: Interest rate swap contracts 8,764 — 8,764 — Interest rate lock commitments 1,627 — 1,627 — Forward loan sale contracts 330 — 330 — Derivative liabilities: Interest rate swap contracts 9,099 — 9,099 — Deferred compensation plan assets 11,632 — 11,632 — Deferred compensation plan liabilities 11,632 — 11,632 — Fair Value Measurements at Reporting Date Using As of December 31, 2016 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment securities available-for-sale: U.S. Treasury notes $ 3,612 $ — $ 3,612 $ — Obligations of U.S. government agencies 391,297 — 391,297 — U.S. agencies mortgage-backed securities & collateralized mortgage obligations 1,213,701 — 1,213,701 — Private mortgage-backed securities 116 — 116 — Other investments 2,972 — 2,972 — Loans held for sale 61,794 — 61,794 — Derivative assets: Interest rate swap contracts 1,332 — 1,332 — Interest rate lock commitments 1,131 — 1,131 — Forward loan sales contracts 286 — 286 — Derivative liabilities Interest rate swap contracts 1,314 — 1,314 — Deferred compensation plan assets 10,627 — 10,627 — Deferred compensation plan liabilities 10,627 — 10,627 — Additionally, from time to time, certain assets are measured at fair value on a non-recurring basis. Adjustments to fair value generally result from the application of lower-of-cost-or-market accounting or write-downs of individual assets due to impairment. The following table presents information about the Company’s assets and liabilities measured at fair value on a non-recurring basis: Fair Value Measurements at Reporting Date Using As of September 30, 2017 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Impaired loans $ 34,489 $ — $ — $ 34,489 Other real estate owned 1,578 — — 1,578 Long-lived assets to be disposed of by sale 356 — — 356 Fair Value Measurements at Reporting Date Using As of December 31, 2016 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Impaired loans $ 39,344 $ — $ — $ 39,344 Other real estate owned 2,110 — — 2,110 Long-lived assets to be disposed of by sale 1,335 — — 1,335 Impaired Loans. Collateralized impaired loans are reported at the fair value of the underlying collateral if repayment is expected solely from collateral. The impaired loans are reported at fair value through specific valuation allowance allocations. In addition, when it is determined that the fair value of an impaired loan is less than the recorded investment in the loan, the carrying value of the loan is adjusted to fair value through a charge to the allowance for loan losses. Collateral values are estimated using independent appraisals and management estimates of current market conditions. As of September 30, 2017 , certain impaired loans with a carrying value of $ 58,523 were reduced by specific valuation allowance allocations of $ 13,903 and partial loan charge-offs of $ 10,131 resulting in a reported fair value of $ 34,489 . As of December 31, 2016 , certain impaired loans with a carrying value of $ 65,238 were reduced by specific valuation allowance allocations of $ 13,954 and partial loan charge-offs of $ 11,941 resulting in a reported fair value of $ 39,344 . OREO. The fair values of OREO are estimated using independent appraisals and management estimates of current market conditions. Upon initial recognition, write-downs based on the foreclosed asset's fair value at foreclosure are reported through charges to the allowance for loan losses. Periodically, the fair value of foreclosed assets is remeasured with any subsequent write-downs charged to OREO expense in the period in which they are identified. Write-downs of $290 during the nine months ended September 30, 2017 included $259 directly related to receipt of updated appraisals and $ 31 based on management estimates of the current fair value of properties. Write downs of $603 during the nine months ended September 30, 2016 included $550 directly related to receipt of updated appraisals and $ 53 based on management estimates of the current fair value of properties. Long-lived Assets to be Disposed of by Sale. Long-lived assets to be disposed of by sale are carried at the lower of carrying value or fair value less estimated costs to sell. The fair values of long-lived assets to be disposed of by sale are based upon observable market data and management estimates of current market conditions. As of September 30, 2017 , the Company had a long-lived asset to be disposed of by sale with a carrying value of $565 that was reduced by write-downs of $209 , resulting in a fair value of $356 . As of December 31, 2016 , the Company had long-lived assets to be disposed of by sale with carrying values aggregating $2,363 that were reduced by write-downs of $1,028 resulting in an aggregate fair value of $1,335 . The following table presents additional quantitative information about assets measured at fair value on a non-recurring basis and for which the Company has utilized Level 3 inputs to determine fair values: Fair Value As of September 30, 2017 December 31, 2016 Valuation Technique Unobservable Inputs Range (Weighted Average) Impaired loans $ 34,489 $ 39,344 Appraisal Appraisal adjustment 0% - 66% (31%) Other real estate owned 1,578 2,110 Appraisal Appraisal adjustment 8% - 96% (18%) Long-lived assets to be disposed of by sale 356 1,335 Appraisal Appraisal adjustment 0% - 9% (6%) The Company is required to disclose the fair value of financial instruments for which it is practical to estimate fair value. The methodologies for estimating the fair value of financial instruments that are measured at fair value on a recurring or non-recurring basis are discussed above. The methodologies for estimating the fair value of other financial instruments are discussed below. For financial instruments bearing a variable interest rate where no credit risk exists, it is presumed that recorded book values are reasonable estimates of fair value. Financial Assets. Carrying values of cash, cash equivalents and accrued interest receivable approximate fair values due to the liquid and/or short-term nature of these instruments. Fair values for investment securities held-to-maturity are obtained from an independent pricing service, which considers observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the investment’s terms and conditions, among other things. Fair values of fixed rate loans and variable rate loans that reprice on an infrequent basis are estimated by discounting future cash flows using current interest rates at which similar loans with similar terms would be made to borrowers of similar credit quality. Carrying values of variable rate loans that reprice frequently, and with no change in credit risk, approximate the fair values of these instruments. Financial Liabilities. The fair values of demand deposits, savings accounts, securities sold under repurchase agreements and accrued interest payable are the amounts payable on demand at the reporting date. The fair values of fixed-maturity certificates of deposit are estimated using external market rates currently offered for deposits with similar remaining maturities. The fair values of derivative liabilities are obtained from an independent pricing service, which considers observable data that may include the three-month LIBOR forward curve, the federal funds effective swap rate and cash flows, among other things. The carrying values of the interest bearing demand notes to the United States Treasury are deemed an approximation of fair values due to the frequent repayment and repricing at market rates. The fixed and floating rate subordinated debentures, floating rate subordinated term loan, notes payable to the FHLB, fixed rate subordinated term debt, and capital lease obligation are estimated by discounting future cash flows using current rates for advances with similar characteristics. Commitments to Extend Credit and Standby Letters of Credit. The fair value of commitments to extend credit and standby letters of credit, based on fees currently charged to enter into similar agreements, is not significant. The estimated fair values of financial instruments that are reported in the Company's consolidated balance sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, are as follows: Fair Value Measurements at Reporting Date Using As of September 30, 2017 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 882,834 $ 882,834 $ 882,834 $ — $ — Investment securities available-for-sale 2,111,697 2,111,697 — 2,111,697 — Investment securities held-to-maturity 505,985 510,405 — 510,405 — Accrued interest receivable 40,621 40,621 — 40,621 — Mortgage servicing rights, net 24,372 38,142 — 38,142 — Loans held for sale 49,729 49,729 — 49,729 — Net loans held for investment 7,427,815 7,163,825 — 7,129,336 34,489 Derivative assets 10,721 10,721 — 10,721 — Deferred compensation plan assets 11,632 11,632 — 11,632 — Total financial assets $ 11,065,406 $ 10,819,606 $ 882,834 $ 9,902,283 $ 34,489 Financial liabilities: Total deposits, excluding time deposits $ 8,751,295 $ 8,751,295 $ 8,751,295 $ — $ — Time deposits 1,182,173 1,172,783 — 1,172,783 — Securities sold under repurchase agreements 635,288 635,288 — 635,288 — Other borrowed funds 30,008 30,008 — 30,008 — Accrued interest payable 5,648 5,648 — 5,648 — Long-term debt 8,039 8,266 — 8,266 — Subordinated debentures held by subsidiary trusts 82,477 92,303 — 92,303 — Derivative liabilities 9,099 9,099 — 9,099 — Deferred compensation plan liabilities 11,632 11,632 — 11,632 — Total financial liabilities $ 10,715,659 $ 10,716,322 $ 8,751,295 $ 1,965,027 $ — Fair Value Measurements at Reporting Date Using As of December 31, 2016 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 782,023 $ 782,023 $ 782,023 $ — $ — Investment securities available-for-sale 1,611,698 1,611,698 — 1,611,698 — Investment securities held-to-maturity 512,770 513,273 — 513,273 — Accrued interest receivable 29,852 29,852 — 29,852 — Mortgage servicing rights, net 18,457 35,656 — 35,656 — Loans held for sale 61,794 61,794 — 61,794 — Net loans held for investment 5,340,536 5,248,127 — 5,208,783 39,344 Derivative assets 2,749 2,749 — 2,749 — Deferred compensation plan assets 10,627 10,627 — 10,627 — Total financial assets $ 8,370,506 $ 8,295,799 $ 782,023 $ 7,474,432 $ 39,344 Financial liabilities: Total deposits, excluding time deposits $ 6,324,512 $ 6,324,512 $ 6,324,512 $ — $ — Time deposits 1,051,598 1,044,670 — 1,044,670 — Securities sold under repurchase agreements 537,556 537,556 — 537,556 — Other borrowed funds 6 6 — 6 — Accrued interest payable 5,421 5,421 — 5,421 — Long-term debt 27,970 27,477 — 27,477 — Subordinated debentures held by subsidiary trusts 82,477 73,554 — 73,554 — Derivative liabilities 1,314 1,314 — 1,314 — Deferred compensation plan liabilities 10,627 10,627 — 10,627 — Total financial liabilities $ 8,041,481 $ 8,025,137 $ 6,324,512 $ 1,700,625 $ —

Recent Authoritative Accounting

Recent Authoritative Accounting Guidance	9 Months Ended
	Sep. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Authoritative Accounting Guidance	Recent Authoritative Accounting Guidance ASU 2014-09 “Revenue from Contracts with Customers.” In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 introduced a new five-step revenue recognition model in which an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also requires disclosures sufficient to enable users to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers, including qualitative and quantitative disclosures about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. ASU 2015-14, “Revenue from Contracts with Customers (Topic 606) – Deferral of the Effective Date” was released in August of 2015 deferring the effective date of ASU 2014-09 for all entities by one year until January 1, 2018. In March 2016, the FASB issued ASU 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal vs Agent Considerations (Reporting Revenue Gross versus Net).” The amendments in ASU 2016-08 were issued to clarify certain principal versus agent considerations within the implementation guidance of ASC Topic 606, “Revenue from Contracts with Customers.” The effective date and transition of ASU 2016-08 is the same as the effective date and transition of ASU 2014-09, Revenue from Contracts with Customers (Topic 606), as discussed above. In April 2016, the FASB issued ASU 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing.” The amendments in ASU 2016-10 were issued to clarify ASC Topic 606, “Revenue from Contracts with Customers” related to (i) identifying performance obligations; and (ii) the licensing implementation guidance. The effective date and transition of ASU 2016-10 is the same as the effective date and transition of ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” as discussed above. The Company will adopt the new revenue recognition standard in the first quarter 2018 using the modified retrospective method of adoption, with a cumulative effect adjustment to the beginning balance of retained earnings, if such an adjustment is deemed significant. The Company's revenue is the sum of net interest income and non-interest income. The scope of the guidance explicitly excludes net interest income, as well as other revenues for financial assets and liabilities, including loans, leases, securities and derivatives. Accordingly, the majority of the Company's revenues will not be affected. The Company expects that ASU 2014-09 will require a change to how certain recurring revenue streams within wealth management and other categories of non-interest income are recognized. However, the Company does not expect these changes to have a significant impact on its results of operations. While the assessment of the aforementioned provisions of ASU 2014-09 is not complete, the Company's accounting policies are not expected to change materially, as the principles of revenue recognition from the updates are largely consistent with existing guidance and current practices. The Company does not anticipate material changes to the timing or amount of revenue recognized, and we will continue to evaluate any impact as additional guidance is issued and internal assessments progress. ASU 2016-01 “Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities.” In January 2016, the FASB issued ASU 2016-10, “Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” The amendments in ASU 2016-1, among other things, (i) require equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income, (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment, (iii) eliminates the requirement for public business entities to disclose the methods 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, (iv) requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, (v) 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, (vi) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements and (viii) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale investment securities. The amendments in ASU 2016-1 will be effective for the Company on January 1, 2018, and are not expected to have a significant impact on the Company’s consolidated financial statements, results of operations or liquidity. ASU 2016-02 “Leases (Topic 842).” In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842).” Under the new guidance, lessees will be required to recognize a lease liability and a right of use asset for all leases (with the exception of short-term leases) at the commencement date of the lease and disclose key information about leasing arrangements. Accounting by lessors is largely unchanged. ASU 2016-02 will be effective for the Company on January 1, 2019 and will be applied using a modified retrospective approach. The Company is evaluating the new guidance to determine the impact ASU 2016-02 will have on its consolidated financial statements, results of operations or liquidity. ASU 2016-05 "Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships." The amendments in ASU 2016-05 clarify that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under ASC Topic 815 does not, in and of itself, require redesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The amendments in ASU 2016-05 became effective for the Company on January 1, 2017, and did not impact the Company’s consolidated financial statements, results of operations or liquidity. ASU 2016-07 "Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting." The amendments in ASU 2016-07 eliminate the requirement that when an investment qualified for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investments, results of operations and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments in ASU 2016-07 also simplify the transition to the equity method of accounting by eliminating retroactive adjustment of the investment when an investment qualifies for use of the equity method, among other things. The amendments in ASU 2016-07 became effective for the Company on January 1, 2017, and did not impact the Company’s consolidated financial statements, results of operations or liquidity. ASU 2016-09 "Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting." Under the amendments in ASU 2016-09, all excess tax benefits and tax deficiencies related to share-based payment awards should be recognized as income tax expense or benefit in the income statement during the period in which they occur. Previously, such amounts were recorded in the pool of excess tax benefits included in additional paid-in capital, if such pool was available. Because excess tax benefits are no longer recognized in additional paid-in capital, the assumed proceeds from applying the treasury stock method when computing earnings per share excludes the amount of excess tax benefits that would have previously been recognized in additional paid-in capital. Additionally, excess tax benefits are classified along with other income tax cash flows as an operating activity rather than a financing activity, as was previously the case. The amendments in ASU 2016-09 also provide that an entity can make an entity-wide accounting policy election to either estimate the number of awards that are expected to vest (current GAAP) or account for forfeitures when they occur. The Company has elected to account for forfeitures when they occur. The amendments in ASU 2016-09 change the threshold to qualify for equity classification to permit withholding up to the maximum statutory tax rates (rather than the minimum as was previously the case) in the applicable jurisdictions. The amendments in ASU 2016-09 became effective for the Company on January 1, 2017, and resulted in a $2.4 reduction in income tax expense during the nine months ended September 30, 2017, of which $1.9 was due to the recognition of excess tax benefits related to outstanding stock option awards exercised during the period and $0.5 was due to the recognition of excess tax benefits related to the vesting of restricted stock. ASU No. 2016-13 "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments." The amendments in ASU 2016-13 require a financial asset or group of financial assets measured at amortized cost basis to be presented on a company's financial statements at the net amount expected to be collected based on historical experience, current conditions and reasonable and supportable forecasts. ASU 2016-13 requires a company's income statement to reflect the measurement of credit losses for newly recognized financial assets as well as the expected increases or decreases of expected credit losses that have taken place during the period. The amendments in ASU 2016-13 require that the allowance for credit losses for purchased financial assets with a more-than-insignificant amount of credit deterioration since origination be measured at amortized cost basis with the initial allowance for credit losses added to the purchase price rather than being reported as a credit loss expense. ASU 2016-13 also requires that credit losses relating to available-for-sale debt securities be recorded through an allowance for credit losses. The amendments in ASU 2016-13 are effective for the Company for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The amendments will be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period. A prospective transition approach is required for debt securities for which other-than-temporary impairment was recognized before the effective date. Amounts previously recognized in accumulated other comprehensive income as of the date of adoption that relate to improvement in cash flows expected to be collected will continue to be accreted into income over the remaining life of the asset. Recoveries of amounts previously written off relating to improvements in cash flows after the date of adoption will be recorded in earnings when received. The Company is currently evaluating the new guidance to determine the impact it will have on its consolidated financial statements, results of operations and liquidity. ASU No. 2016-15 "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments." The amendments in ASU 2016-15 are intended to reduce diversity in practice in how eight particular transactions are classified in the statement of cash flows. The amendments in ASU 2016-15 are effective for the Company on January 1, 2018. Early adoption is permitted, provided that all of the amendments are adopted in the same period. Entities will be required to apply the guidance retrospectively. If it is impracticable to apply the guidance retrospectively for an issue, the amendments related to that issue would be applied prospectively. The amendments in ASU 2016-15 only affect the classification of certain items within the statement of cash flows, and are not expected to have a significant impact on the Company’s consolidated financial statements, results of operations or liquidity. ASU No. 2017-01 "Business Combinations (Topic 805): Clarifying the Definition of a Business.” ASU 2017-01 clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this update provide a screen to determine when a set is not a business. The screen requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. This screen reduces the number of transactions that need to be further evaluated. If the screen is not met, the amendments in this update (1) require that to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output and (2) remove the evaluation of whether a market participant could replace missing elements. The amendments provide a framework to assist entities in evaluating whether both an input and a substantive process are present. The framework includes two sets of criteria to consider that depend on whether a set has outputs. ASU 2017-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. As we approach the effective date, we will consult the framework to determine the impact on the Company's consolidated financial statements, results of operations or liquidity. ASU No. 2017-04, “Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” The amendments in ASU 2017-04 remove Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. Goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. All other goodwill impairment guidance will remain largely unchanged. ASU No. 2017-04 is effective for interim and annual reporting periods beginning after December 15, 2019, applied prospectively. Early adoption is permitted for any impairment tests performed after January 1, 2017. The amendments in ASU 2017-04 are not expected to have a significant impact on the Company’s consolidated financial statements, results of operations or liquidity. ASU No. 2017-07, “Compensation - Retirement Benefits (Topic 750): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.” The amendments in ASU 2017-07 requires employers to present the service cost component of the net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. The other components of net benefit cost are required to be presented in the income separately from the service cost component and outside a subtotal of income from operations, if one is presented. The amendments in ASU 2017-07 also allow only the service cost component to be eligible for capitalization. ASU No. 2017-07 is effective for the Company for interim and annual reporting periods beginning after December 15, 2017, with early adoption permitted. The amendments in ASU 2017-07 are applied retrospectively for the presentation of the service cost and other components of net periodic benefit cost in the income statement and prospectively for the capitalization of the service cost in other assets. ASU 2017-07 allows the use of a practical expedient that permits an employer to use the amounts disclosed in its pension and other post-retirement benefits plan footnote for the prior comparative periods as the estimation basis for applying the retrospective presentation requirements. Adoption of the amendments in ASU 2017-07 will not have a significant impact on the Company’s consolidated financial statements, results of operations or liquidity. ASU No. 2017-08, “Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities.” The amendments in ASU 2017-08 shorten the amortization period for the premium on certain purchased callable debt securities to the earliest call date. The new guidance does not change the accounting for purchased callable debt securities held at a discount; the discount continues to be amortized to maturity. ASU No. 2017-08 is effective for interim and annual reporting periods beginning after December 15, 2018, with early adoption permitted. The guidance calls for a modified retrospective transition approach under which a cumulative-effect adjustment will be made to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. The Company currently amortizes premiums on callable debt securities to the earliest call date. As such, the amendments in ASU 2017-08 will not impact the Company's consolidated financial statements, results of operations and liquidity. ASU 2017-09, "Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting." In May 2017, the FASB issued ASU 2017-09, which clarifies when a change to the terms or conditions of a share-based payment award must be accounted for as a modification. Under the new guidance, an entity will not apply modification accounting to a share-based payment award if there is no change to the award's fair value, vesting conditions and classification as an equity or liability instrument. The guidance is effective prospectively for all companies for annual periods beginning after December 15, 2017. Early adoption is permitted. The Company is currently evaluating the impact the standard may have on its consolidated financial statements, results of operations and liquidity. ASU 2017-12, "Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities." In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12). The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. ASU 2017-12 is effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. The Company plans to adopt ASU 2017-12 on January 1, 2018. ASU 2017-12 requires a modified retrospective transition method in which the Company will recognize the cumulative effect of the change on the beginning balance of each affected component of equity in the statement of financial position as of the date of adoption. While the Company continues to assess all potential impacts of the standard, we currently expect adoption to have an immaterial impact on our consolidated financial statements.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Subsequent events have been evaluated for potential recognition and disclosure through the date financial statements were filed with the SEC. On October 16, 2017 , the Company declared a quarterly dividend to common shareholders of $ 0.24 per share, to be paid on November 13, 2017 to shareholders of record as of October 31, 2017 . No other events requiring recognition or disclosure were identified.

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the consideration paid, fair values of the Cascade assets acquired and liabilities assumed, and the resulting goodwill. Due to the recent closing of the transaction, all amounts reported are provisional pending the review of valuations obtained from third parties. As Recorded Fair Value As Recorded As of May 30, 2017 by Cascade Adjustments by the Company Assets acquired: Cash and cash equivalents $ 246,804 $ — $ 246,804 Investment securities 476,733 4,876 (1) 481,609 Loans held for investment 2,112,077 (31,703 ) (2) 2,080,374 Mortgage loans held for sale 10,253 6 (2) 10,259 Allowance for loan loss (23,974 ) 23,974 (3) — Premises and equipment 46,554 178 (4) 46,732 Other real estate owned ("OREO") 1,192 — 1,192 Core deposit intangible — 47,968 (5) 47,968 Deferred tax assets 47,653 (21,661 ) (6) 25,992 Other assets 98,570 1,136 (7) 99,706 Total assets acquired 3,015,862 24,774 3,040,636 Liabilities assumed: Deposits 2,669,910 (934 ) (8) 2,668,976 Accounts Payable and Accrued Expense 62,150 720 (9) 62,870 Total liabilities assumed 2,732,060 (214 ) 2,731,846 Net assets acquired $ 283,802 $ 24,988 $ 308,790 Consideration paid: Cash $ 155,029 Class A common stock 385,969 Total consideration paid 540,998 Goodwill $ 232,208 Explanation of fair value adjustments. Note that certain marks have been updated since prior quarter, and certain balances have been reclassified, none of which are material: (1) Write up of the book value of investments to their estimated fair values on the date of acquisition based upon quotes obtained from an independent third party pricing service. (2) Write down of the book value of loans to their estimated fair values. Shared National Credits (SNC) were recorded at quoted sales prices where available. The fair value of the remaining loans was estimated using cash flow projections based on the remaining maturity and repricing terms, adjusted for estimated future credit losses and prepayments and discounted to present value using a risk-adjusted market rate for similar loans. The fair value of collateral dependent loans acquired with deteriorated credit quality was estimated based on the Company's analysis of the fair value of each loan's underlying collateral, discounted using market-derived rates of return with consideration given to the period of time and costs associated with foreclosure and disposition of the collateral. (3) Adjustment to remove the Cascade allowance for loan losses at acquisition date, as the credit risk is accounted for in the fair value adjustment for loans receivable described in (2) above. (4) Write up of the book value of premises and equipment to their estimated fair values on the date of acquisition based upon appraisals obtained from an independent third party appraiser or broker's opinion of value. (5) Adjustment represents the value of the core deposit base assumed in the acquisition based upon valuation from an independent accounting and advisory firm. (6) Adjustment consists of the write-off of pre-existing deferred tax assets as a result of the acquisition. (7) Adjustment consists of various other assets recorded as a result of the acquisition, including mortgage servicing rights, SBA servicing rights, and favorable leases offset by reductions to the fair value of other items. (8) Decrease in book value of time deposits to their estimated fair values based upon interest rates of similar time deposits with similar terms on the date of acquisition based upon valuation from an independent accounting and advisory firm. (9) Increase in fair value due to credit card incentive program, unfavorable leases, write-off of balance sheet reserve, and swap liability offset.
Summary of Pre-tax Merger Related Expenses	These costs are incorporated in non-interest expenses in the Company’s consolidated statements of income and are summarized below. Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 Legal and Professional Fees $ 2,498 $ 8,995 Employee Expenses 1,755 5,041 Technology Conversion and Contract Termination 7,090 7,779 Other 1,673 2,039 Total Acquisition Related Expenses $ 13,016 $ 23,854
Schedule of Acquired Loans with Credit Impairment	Information regarding acquired credit-impaired loans as of the May 30, 2017 acquisition date is as follows: Contractually required principal and interest payments $ 48,041 Contractual cash flows not expected to be collected ("non-accretable discount") 23,376 Cash flows expected to be collected 24,665 Interest component of cash flows expected to be collected ("accretable discount") 1,901 Fair value of acquired credit-impaired loans $ 22,764 The following table displays the outstanding unpaid balances and accrual status of loans acquired with credit impairment as of September 30, 2017 and 2016 : As of September 30, 2017 2016 Outstanding balance $ 46,199 $ 38,505 Carrying value Loans on accrual status 30,804 23,665 Total carrying value $ 30,804 $ 23,665 The following table summarizes changes in the accretable yield for loans acquired credit impaired for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Beginning balance $ 7,650 $ 5,905 $ 6,803 $ 6,713 Additions 167 1,114 2,096 1,114 Accretion income (858 ) (670 ) (2,131 ) (1,899 ) Reductions due to exit events (143 ) (595 ) (1,131 ) (900 ) Reclassifications from nonaccretable differences 498 729 1,677 1,455 Ending balance $ 7,314 $ 6,483 $ 7,314 $ 6,483
Schedule of Acquired Loans not Deemed to Have Credit Impairment	Information regarding acquired loans not deemed credit-impaired at the acquisition date is as follows: Contractually required principal and interest payments $ 2,098,452 Contractual cash flows not expected to be collected due to projected prepayment 23,387 Fair value at acquisition $ 2,067,869
Summary of Pro Forma Information	The following table presents unaudited supplemental pro forma consolidated revenues and net income as if the acquisition had occurred as of January 1, 2016. Three months ended September 30, Nine months ended September 30, 2017 2016 2017 2016 Interest income $ 108,765 $ 99,288 $ 312,091 $ 289,060 Non-interest income 38,274 39,811 116,171 114,881 Total revenues $ 147,039 $ 139,099 $ 428,262 $ 403,941 Net income $ 34,903 $ 28,769 $ 94,017 $ 44,317 EPS - basic $ 0.52 $ 0.52 $ 1.55 $ 0.79 EPS - diluted 0.51 0.51 1.53 0.79

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	The following table sets forth activity for CDI for the three and nine months ended September 30, 2017 and 2016: Three months ended Nine months ended September 30, September 30, 2017 2016 2017 2016 CDI, net, beginning of period $ 52,837 $ 8,935 $ 9,648 $ 10,589 Established through acquisitions or provisional adjustments 19 2,486 47,968 2,486 Reductions due to sale of accounts — — (3,068 ) — CDI current period amortization (1,885 ) (875 ) (3,577 ) (2,529 ) Total CDI, net, at September 30 $ 50,971 $ 10,546 $ 50,971 $ 10,546
Schedule of Future Amortization Expense	The following table provides the estimated future CDI amortization expense: Years Ending December 31, 2017 remaining $ 1,298 2018 5,093 2019 4,994 2020 4,872 2021 4,729 Thereafter 29,985

Investment Securities (Tables)

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Amortized Cost and Approximate Fair Values of Investment Securities	The amortized cost and approximate fair values of investment securities are summarized as follows: September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Available-for-Sale: U.S. Treasury notes $ 3,206 $ 1 $ (2 ) $ 3,205 Obligations of U.S. government agencies 508,449 338 (3,209 ) 505,578 U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 1,431,125 8,829 (4,716 ) 1,435,238 Private mortgage-backed securities 97,715 313 (190 ) 97,838 Corporate securities 66,754 126 (2 ) 66,878 Other investments 2,951 9 — 2,960 Total $ 2,110,200 $ 9,616 $ (8,119 ) $ 2,111,697 September 30, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Held-to-Maturity: State, county and municipal securities $ 180,981 $ 3,726 $ (123 ) $ 184,584 U.S agency residential mortgage-backed securities & 243,380 10,725 (10,172 ) 243,933 Obligations of U.S. government agencies 19,737 43 (19 ) 19,761 Corporate securities 61,704 272 (33 ) 61,943 Other investments 183 1 — 184 Total $ 505,985 $ 14,767 $ (10,347 ) $ 510,405 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Available-for-Sale: U.S. Treasury notes $ 3,608 $ 5 $ (1 ) $ 3,612 Obligations of U.S. government agencies 397,411 343 (6,457 ) 391,297 U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 1,220,890 6,412 (13,601 ) 1,213,701 Private mortgage-backed securities 116 1 (1 ) 116 Other investments 2,951 21 — 2,972 Total $ 1,624,976 $ 6,782 $ (20,060 ) $ 1,611,698 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Held-to-Maturity: State, county and municipal securities $ 160,192 $ 2,723 $ (542 ) $ 162,373 Obligations of U.S. government agencies 19,737 — (162 ) 19,575 U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 279,578 7,804 (9,249 ) 278,133 Corporate securities 53,032 139 (211 ) 52,960 Other investments 231 1 — 232 Total $ 512,770 $ 10,667 $ (10,164 ) $ 513,273
Realized Gains (Losses) on Investments	Gross realized gains and losses from the disposition of investment securities are summarized in the following table: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Gross realized gains $ 1,072 $ 239 $ 1,079 $ 404 Gross realized losses (301 ) (14 ) (301 ) (92 )
Gross Unrealized Losses and Fair Values of Investment Securities	The following tables show the gross unrealized losses and fair values of investment securities, aggregated by investment category, and the length of time individual investment securities have been in a continuous unrealized loss position, as of September 30, 2017 and December 31, 2016 : Less than 12 Months 12 Months or More Total September 30, 2017 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Available-for-Sale: U.S. Treasury notes $ 2,201 $ (2 ) $ — $ — $ 2,201 $ (2 ) Obligations of U.S. government agencies 303,060 (2,458 ) 86,718 (751 ) 389,778 (3,209 ) U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 556,771 (3,731 ) 74,732 (985 ) 631,503 (4,716 ) Private mortgage-backed securities 30,518 (189 ) 31 (1 ) 30,549 (190 ) Corporate securities 6,987 (2 ) — — 6,987 (2 ) Total $ 899,537 $ (6,382 ) $ 161,481 $ (1,737 ) $ 1,061,018 $ (8,119 ) Less than 12 Months 12 Months or More Total September 30, 2017 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Held-to-Maturity: State, county and municipal securities $ 25,207 $ (97 ) $ 4,208 $ (26 ) $ 29,415 $ (123 ) U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 38,712 (8,814 ) 18,846 (1,358 ) 57,558 (10,172 ) Obligations of U.S. government agencies 9,972 (19 ) — — 9,972 (19 ) Corporate securities 3,966 — 5,017 (33 ) 8,983 (33 ) Total $ 77,857 $ (8,930 ) $ 28,071 $ (1,417 ) $ 105,928 $ (10,347 ) Less than 12 Months 12 Months or More Total December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Available-for-Sale: U.S. Treasury notes $ 598 $ (1 ) $ — $ — $ 598 $ (1 ) Obligations of U.S. government agencies 316,511 (6,457 ) — — 316,511 (6,457 ) U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 746,265 (13,102 ) 15,801 (499 ) 762,066 (13,601 ) Private mortgage-backed securities — — 48 (1 ) 48 (1 ) Total $ 1,063,374 $ (19,560 ) $ 15,849 $ (500 ) $ 1,079,223 $ (20,060 ) Less than 12 Months 12 Months or More Total December 31, 2016 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Held-to-Maturity: State, county and municipal securities $ 42,518 $ (533 ) $ 2,831 $ (9 ) $ 45,349 $ (542 ) Obligations of U.S. government agencies 19,575 (162 ) — — 19,575 (162 ) U.S. agency residential mortgage-backed securities & collateralized mortgage obligations 108,857 (7,973 ) 19,986 (1,276 ) 128,843 (9,249 ) Corporate securities 32,474 (211 ) — — 32,474 (211 ) Total $ 203,424 $ (8,879 ) $ 22,817 $ (1,285 ) $ 226,241 $ (10,164 )
Maturities of Investment Securities	Maturities of investment securities at September 30, 2017 are shown below. Maturities of mortgage-backed securities have been adjusted to reflect shorter maturities based upon estimated prepayments of principal. All other investment securities maturities are shown at contractual maturity dates. Available-for-Sale Held-to-Maturity September 30, 2017 Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Within one year $ 375,199 $ 376,264 $ 87,077 $ 83,899 After one year but within five years 1,287,854 1,288,384 264,417 272,442 After five years but within ten years 278,782 278,277 119,579 121,039 After ten years 168,365 168,772 34,912 33,025 Total $ 2,110,200 $ 2,111,697 $ 505,985 $ 510,405

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Schedule of Recorded Investment in Past Due Loans by Class	The following tables present the Company's recorded investment and contractual aging of the Company's recorded investment in loans by class as of the dates indicated. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Total Loans 30 - 59 60 - 89 > 90 30 or More Days Days Days Days Current Non-accrual Total As of September 30, 2017 Past Due Past Due Past Due Past Due Loans Loans Loans Real estate Commercial $ 4,582 $ 1,160 $ 2,502 $ 8,244 $ 2,722,265 $ 28,042 $ 2,758,551 Construction: Land acquisition & development 1,656 493 65 2,214 345,234 4,720 352,168 Residential 1,245 1,598 470 3,313 230,533 205 234,051 Commercial — — — — 113,173 3,844 117,017 Total construction loans 2,901 2,091 535 5,527 688,940 8,769 703,236 Residential 8,502 6,313 187 15,002 1,478,314 5,711 1,499,027 Agricultural 1,327 8,533 — 9,860 148,219 2,218 160,297 Total real estate loans 17,312 18,097 3,224 38,633 5,037,738 44,740 5,121,111 Consumer: Indirect consumer 6,840 1,659 347 8,846 778,434 1,505 788,785 Other consumer 1,391 498 68 1,957 175,275 358 177,590 Credit card 1,043 408 671 2,122 70,087 — 72,209 Total consumer loans 9,274 2,565 1,086 12,925 1,023,796 1,863 1,038,584 Commercial 3,308 1,094 1,077 5,479 1,154,196 26,532 1,186,207 Agricultural 1,769 97 278 2,144 149,192 1,345 152,681 Other, including overdrafts — — — — 3,804 — 3,804 Loans held for investment 31,663 21,853 5,665 59,181 7,368,726 74,480 7,502,387 Mortgage loans originated for sale — — — — 49,729 — 49,729 Total loans $ 31,663 $ 21,853 $ 5,665 $ 59,181 $ 7,418,455 $ 74,480 $ 7,552,116 Total Loans 30 - 59 60 - 89 > 90 30 or More Days Days Days Days Current Non-accrual Total As of December 31, 2016 Past Due Past Due Past Due Past Due Loans Loans Loans Real estate Commercial $ 7,307 $ 1,099 $ 303 $ 8,709 $ 1,799,525 $ 26,211 $ 1,834,445 Construction: Land acquisition & development 633 352 279 1,264 202,223 5,025 208,512 Residential 931 264 — 1,195 146,245 456 147,896 Commercial — — — — 124,827 762 125,589 Total construction loans 1,564 616 279 2,459 473,295 6,243 481,997 Residential 3,986 1,280 702 5,968 1,014,990 6,435 1,027,393 Agricultural 341 287 — 628 165,293 4,327 170,248 Total real estate loans 13,198 3,282 1,284 17,764 3,453,103 43,216 3,514,083 Consumer: Indirect consumer 8,425 2,329 712 11,466 740,163 780 752,409 Other consumer 1,322 235 167 1,724 146,006 357 148,087 Credit card 504 333 567 1,404 68,366 — 69,770 Total consumer loans 10,251 2,897 1,446 14,594 954,535 1,137 970,266 Commercial 3,171 727 734 4,632 767,878 25,432 797,942 Agricultural 1,518 362 14 1,894 127,956 3,008 132,858 Other, including overdrafts — 1 311 312 1,289 — 1,601 Loans held for investment 28,138 7,269 3,789 39,196 5,304,761 72,793 5,416,750 Mortgage loans originated for sale — — — — 61,794 — 61,794 Total loans $ 28,138 $ 7,269 $ 3,789 $ 39,196 $ 5,366,555 $ 72,793 $ 5,478,544
Schedule of Acquired Loans with Credit Impairment	Information regarding acquired credit-impaired loans as of the May 30, 2017 acquisition date is as follows: Contractually required principal and interest payments $ 48,041 Contractual cash flows not expected to be collected ("non-accretable discount") 23,376 Cash flows expected to be collected 24,665 Interest component of cash flows expected to be collected ("accretable discount") 1,901 Fair value of acquired credit-impaired loans $ 22,764 The following table displays the outstanding unpaid balances and accrual status of loans acquired with credit impairment as of September 30, 2017 and 2016 : As of September 30, 2017 2016 Outstanding balance $ 46,199 $ 38,505 Carrying value Loans on accrual status 30,804 23,665 Total carrying value $ 30,804 $ 23,665 The following table summarizes changes in the accretable yield for loans acquired credit impaired for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Beginning balance $ 7,650 $ 5,905 $ 6,803 $ 6,713 Additions 167 1,114 2,096 1,114 Accretion income (858 ) (670 ) (2,131 ) (1,899 ) Reductions due to exit events (143 ) (595 ) (1,131 ) (900 ) Reclassifications from nonaccretable differences 498 729 1,677 1,455 Ending balance $ 7,314 $ 6,483 $ 7,314 $ 6,483
Schedule of Recorded Investment in Impaired Loans	The following tables present information on the Company’s recorded investment in impaired loans as of dates indicated: As of September 30, 2017 Unpaid Total Principal Balance Recorded Investment With No Allowance Recorded Investment With Allowance Total Recorded Investment Related Allowance Real estate: Commercial $ 47,934 $ 21,558 $ 16,035 $ 37,593 $ 3,947 Construction: Land acquisition & development 11,290 3,694 1,714 5,408 711 Residential 310 205 — 205 — Commercial 4,725 417 3,537 3,954 2,148 Total construction loans 16,325 4,316 5,251 9,567 2,859 Residential 8,990 5,629 2,122 7,751 218 Agricultural 2,681 2,425 156 2,581 4 Total real estate loans 75,930 33,928 23,564 57,492 7,028 Consumer 27 — 25 25 14 Commercial 36,787 14,623 16,748 31,371 6,426 Agricultural 1,585 951 609 1,560 435 Total $ 114,329 $ 49,502 $ 40,946 $ 90,448 $ 13,903 As of December 31, 2016 Unpaid Total Principal Balance Recorded Investment With No Allowance Recorded Investment With Allowance Total Recorded Investment Related Allowance Real estate: Commercial $ 57,017 $ 24,410 $ 21,420 $ 45,830 $ 2,847 Construction: Land acquisition & development 12,084 4,330 1,813 6,143 826 Residential 1,555 219 619 838 1 Commercial 4,786 3,940 647 4,587 657 Total construction loans 18,425 8,489 3,079 11,568 1,484 Residential 8,222 4,074 2,470 6,544 253 Agricultural 5,069 4,509 181 4,690 4 Total real estate loans 88,733 41,482 27,150 68,632 4,588 Commercial 40,314 13,230 19,167 32,397 9,254 Agricultural 3,738 3,280 382 3,662 112 Total $ 132,785 $ 57,992 $ 46,699 $ 104,691 $ 13,954 The following table presents the average recorded investment in and income recognized on impaired loans for the periods indicated: Three Months Ended September 30, 2017 2016 Average Recorded Investment Income Recognized Average Recorded Investment Income Recognized Real estate: Commercial $ 40,362 $ 54 $ 33,408 $ 100 Construction: Land acquisition & development 5,383 2 6,797 13 Residential 207 — 274 — Commercial 4,192 1 1,055 1 Total construction loans 9,782 3 8,126 14 Residential 7,123 4 3,282 4 Agricultural 2,642 — 4,786 2 Total real estate loans 59,909 61 49,602 120 Consumer 25 — — Commercial 31,637 47 30,123 72 Agricultural 2,270 — 2,249 — Total $ 93,841 $ 108 $ 81,974 $ 192 Nine Months Ended September 30, 2017 2016 Average Recorded Investment Income Recognized Average Recorded Investment Income Recognized Real estate: Commercial $ 41,712 $ 281 $ 35,572 $ 241 Construction: Land acquisition & development 5,776 10 6,992 32 Residential 522 — 279 — Commercial 4,271 45 1,007 3 Total construction loans 10,569 55 8,278 35 Residential 7,148 12 4,219 7 Agricultural 3,636 — 4,607 3 Total real estate loans 63,065 348 52,676 286 Consumer 13 — — — Commercial 31,884 156 27,781 128 Agricultural 2,611 2 2,341 — Total $ 97,573 $ 506 $ 82,798 $ 414
Schedule of Loans Renegotiated in Troubled Debt Restructurings	The Company considers a payment default to occur on troubled debt restructurings when the loan is 90 days or more past due or was placed on non-accrual status after the modification. Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 Number of Notes Balance Number of Notes Balance Commercial real estate 1 $ 177 2 $ 2,407 Commercial construction — — 1 3,528 Commercial 1 1,300 1 1,300 Total 2 $ 1,477 4 $ 7,235 The following table presents information on the Company's troubled debt restructurings that occurred during the three and nine months ended September 30, 2017 : Number of Notes Type of Concession Principal Balance at Restructure Date Three Months Ended September 30, 2017 Interest only period Extension of term or amortization schedule Interest rate adjustment Other (1) Commercial 1 — — — 611 611 Total loans restructured during period 1 $ — $ — $ — $ 611 $ 611 (1) Other includes concessions that reduce or defer payments for a specified period of time and/or concessions that do not fit into other designated categories. Number of Notes Type of Concession Principal Balance at Restructure Date Nine Months Ended September 30, 2017 Interest only period Extension of terms or maturity Interest rate adjustment Other (1) Commercial real estate 5 $ 1,475 $ 388 $ — $ 909 $ 2,772 Commercial 16 511 1,968 — 6,057 8,536 Total loans restructured during period 21 $ 1,986 $ 2,356 $ — $ 6,966 $ 11,308 (1) Other includes concessions that reduce or defer payments for a specified period of time and/or do not fit into other designated categories.
Schedule of Recorded Investment in Criticized Loans by Class and Credit Quality Indicator	The following tables present the Company’s recorded investment in criticized loans by class and credit quality indicator based on the most recent analysis performed as of the dates indicated: As of September 30, 2017 Other Assets Especially Mentioned Substandard Doubtful Total Criticized Loans Real estate: Commercial $ 79,921 $ 107,791 $ 12,025 $ 199,737 Construction: Land acquisition & development 5,425 13,818 1,597 20,840 Residential 3,690 2,201 — 5,891 Commercial 2,564 3,842 3,747 10,153 Total construction loans 11,679 19,861 5,344 36,884 Residential 4,607 11,664 1,039 17,310 Agricultural 1,212 23,574 — 24,786 Total real estate loans 97,419 162,890 18,408 278,717 Consumer: Indirect consumer 660 2,116 120 2,896 Other consumer 458 849 140 1,447 Total consumer loans 1,118 2,965 260 4,343 Commercial 43,365 61,612 16,495 121,472 Agricultural 5,219 11,859 979 18,057 Total $ 147,121 $ 239,326 $ 36,142 $ 422,589 As of December 31, 2016 Other Assets Especially Mentioned Substandard Doubtful Total Criticized Loans Real estate: Commercial $ 85,292 $ 85,293 $ 10,842 $ 181,427 Construction: Land acquisition & development 13,414 6,214 1,401 21,029 Residential 412 1,621 656 2,689 Commercial 1,555 6,344 664 8,563 Total construction loans 15,381 14,179 2,721 32,281 Residential 5,038 12,472 764 18,274 Agricultural 3,831 17,813 — 21,644 Total real estate loans 109,542 129,757 14,327 253,626 Consumer: Indirect consumer 778 1,527 101 2,406 Other consumer 681 1,036 264 1,981 Total consumer loans 1,459 2,563 365 4,387 Commercial 46,402 29,281 21,240 96,923 Agricultural 6,178 10,724 404 17,306 Total $ 163,581 $ 172,325 $ 36,336 $ 372,242

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Schedule of Allowance for Loan Losses by Portfolio Segment	The following tables present a summary of changes in the allowance for loan losses by portfolio segment for the periods indicated: Three Months Ended September 30, 2017 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Beginning balance $ 33,498 $ 7,554 $ 33,124 $ 1,525 $ — $ 75,701 Provision charged to operating expense (690 ) 2,620 1,530 (17 ) — 3,443 Less loans charged-off (1,695 ) (3,115 ) (2,609 ) (41 ) — (7,460 ) Add back recoveries of loans previously charged-off 613 962 1,313 — — 2,888 Ending balance $ 31,726 $ 8,021 $ 33,358 $ 1,467 $ — $ 74,572 Nine Months Ended September 30, 2017 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Beginning balance $ 28,625 $ 7,711 $ 38,092 $ 1,786 $ — $ 76,214 Provision charged to operating expense 4,775 5,157 (2,145 ) (259 ) — 7,528 Less loans charged-off (2,938 ) (8,123 ) (4,450 ) (111 ) — (15,622 ) Add back recoveries of loans previously charged-off 1,264 3,276 1,861 51 — 6,452 Ending balance $ 31,726 $ 8,021 $ 33,358 $ 1,467 $ — $ 74,572 As of September 30, 2017 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Loans individually evaluated for impairment $ 7,028 $ 14 $ 6,426 $ 435 $ — $ 13,903 Loans collectively evaluated for impairment 24,698 8,007 26,932 1,032 — 60,669 Allowance for loan losses $ 31,726 $ 8,021 $ 33,358 $ 1,467 $ — $ 74,572 Loans held for investment: Individually evaluated for impairment $ 57,492 $ 25 $ 31,371 $ 1,560 $ — $ 90,448 Collectively evaluated for impairment 5,063,619 1,038,559 1,154,836 151,121 3,804 7,411,939 Total loans $ 5,121,111 $ 1,038,584 $ 1,186,207 $ 152,681 $ 3,804 $ 7,502,387 Three Months Ended September 30, 2016 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Beginning balance $ 32,281 $ 6,315 $ 39,995 $ 1,749 $ — $ 80,340 Provision charged to operating expense (352 ) 2,395 265 55 — 2,363 Less loans charged-off (379 ) (2,157 ) (579 ) — — (3,115 ) Add back recoveries of loans previously charged-off 221 742 680 4 — 1,647 Ending balance $ 31,771 $ 7,295 $ 40,361 $ 1,808 $ — $ 81,235 Nine Months Ended September 30, 2016 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Beginning balance $ 52,296 $ 5,144 $ 18,775 $ 602 $ — $ 76,817 Provision charged to operating expense (20,492 ) 5,747 22,268 1,390 — 8,913 Less loans charged-off (2,824 ) (5,761 ) (2,085 ) (188 ) — (10,858 ) Add back recoveries of loans previously charged-off 2,791 2,165 1,403 4 — 6,363 Ending balance $ 31,771 $ 7,295 $ 40,361 $ 1,808 $ — $ 81,235 As of December 31, 2016 Real Estate Consumer Commercial Agriculture Other Total Allowance for loan losses: Loans individually evaluated for impairment $ 4,588 $ — $ 9,254 $ 112 $ — $ 13,954 Loans collectively evaluated for impairment 24,037 7,711 28,838 1,674 — 62,260 Allowance for loan losses $ 28,625 $ 7,711 $ 38,092 $ 1,786 $ — $ 76,214 Loans held for investment: Individually evaluated for impairment $ 68,632 $ — $ 32,397 $ 3,662 $ — $ 104,691 Collectively evaluated for impairment 3,445,451 970,266 765,545 129,196 1,601 5,312,059 Total loans $ 3,514,083 $ 970,266 $ 797,942 $ 132,858 $ 1,601 $ 5,416,750

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	9 Months Ended
	Sep. 30, 2017
Repossessed Assets [Abstract]
Other Real Estate Owned Roll Forward	Information with respect to the Company's other real estate owned follows: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Beginning balance $ 11,286 $ 7,908 $ 10,019 $ 6,254 OREO acquired through acquisition — 1,120 1,192 1,120 Additions 1,419 1,316 3,182 5,335 Valuation adjustments (238 ) — (294 ) (603 ) Dispositions (2,123 ) (897 ) (3,755 ) (2,659 ) Ending balance $ 10,344 $ 9,447 $ 10,344 $ 9,447

Derivatives and Hedging Activ32

Derivatives and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts and Estimated Fair Values of Derivatives	The notional amounts and estimated fair values of the Company's derivatives are presented in the following table. Fair value estimates are obtained from third parties and are based on pricing models. September 30, 2017 December 31, 2016 Notional Amount Estimated Fair Value Notional Amount Estimated Fair Value Derivative Assets (included in other assets): Non-hedging interest rate derivatives: Interest rate swap contracts $ 327,569 $ 8,764 $ 53,593 $ 1,332 Interest rate lock commitments 78,720 1,627 73,422 1,131 Forward loan sales contracts 104,543 330 126,836 286 Total derivative assets $ 510,832 $ 10,721 $ 253,851 $ 2,749 Derivative Liabilities (included in accounts payable and accrued expenses): Derivatives designated as hedges: Interest rate swap contracts $ — $ — $ 100,000 $ 33 Non-hedging interest rate derivatives: Interest rate swap contracts 327,569 9,099 53,593 1,281 Total derivative liabilities $ 327,569 $ 9,099 $ 153,593 $ 1,314
Offsetting Assets and Liabilities	The following table illustrates the potential effect of the Company's master netting arrangements, by type of financial instrument, on the Company's consolidated balance sheets as of September 30, 2017 and December 31, 2016: September 30, 2017 Gross Amounts Recognized Gross Amounts Offset in the Balance Sheet Net Amounts in the Balance Sheet Financial Instruments Fair Value of Financial Collateral in the Balance Sheet Net Amount Financial Assets Interest rate swap contracts $ 8,764 $ — $ 8,764 $ 1,530 $ — $ 7,234 Mortgage related derivatives 1,957 — 1,957 — — 1,957 Total derivatives 10,721 — 10,721 1,530 — 9,191 Total assets $ 10,721 $ — $ 10,721 $ 1,530 $ — $ 9,191 Financial Liabilities Interest rate swap contracts $ 9,099 $ — $ 9,099 $ 1,530 $ 7,569 $ — Total derivatives 9,099 — 9,099 1,530 7,569 — Repurchase agreements 635,288 — 635,288 — 635,288 — Total liabilities $ 644,387 $ — $ 644,387 $ 1,530 $ 642,857 $ — December 31, 2016 Gross Amounts Recognized Gross Amounts Offset in the Balance Sheet Net Amounts in the Balance Sheet Financial Instruments Fair Value of Financial Collateral in the Balance Sheet Net Amount Financial Assets Interest rate swap contracts $ 1,332 $ — $ 1,332 $ 479 $ — $ 853 Mortgage related derivatives 1,417 — 1,417 — — 1,417 Total derivatives 2,749 — 2,749 479 — 2,270 Total assets $ 2,749 $ — $ 2,749 $ 479 $ — $ 2,270 Financial Liabilities Interest rate swap contracts $ 1,314 $ — $ 1,314 $ 479 $ — $ 835 Total derivatives 1,314 — 1,314 479 — 835 Repurchase agreements 537,556 — 537,556 — 537,556 — Total liabilities $ 538,870 $ — $ 538,870 $ 479 $ 537,556 $ 835
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)	The following table presents the pre-tax gains or losses related to derivative contracts that were recorded in accumulated other comprehensive income and other non-interest income in the Company's statements of income for the periods indicated: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Derivatives designated as hedges: Amount of loss recognized in other comprehensive income (effective portion) $ (658 ) $ 512 $ (1,095 ) $ (2,490 ) Reclassification adjustment for derivatives net (gains) losses included in income 1,128 — 1,128 — Non-hedging interest rate derivatives: Amount of gain (loss) recognized in other non-interest income 24 (3 ) (49 ) (82 ) Amount of net fee income recognized in other non-interest income 162 — 441 245 Amount of net gains recognized in mortgage banking revenues 358 752 539 1,970

Earnings per Common Share (Tabl

Earnings per Common Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings per Share	The following table sets forth the computation of basic and diluted earnings per share for the three and nine month periods ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Net income $ 27,259 $ 25,193 $ 72,253 $ 70,871 Weighted average common shares outstanding for basic earnings per share computation 56,094,401 44,415,213 49,514,818 44,505,544 Dilutive effects of stock-based compensation 436,467 390,708 486,064 379,368 Weighted average common shares outstanding for diluted earnings per common share computation 56,530,868 44,805,921 50,000,882 44,884,912 Basic earnings per common share $ 0.49 $ 0.57 $ 1.46 $ 1.59 Diluted earnings per common share $ 0.48 $ 0.56 $ 1.45 $ 1.58 Anti-dilutive unvested time restricted stock — 135 94,210 95,886

Regulatory Capital (Tables)

Regulatory Capital (Tables)	9 Months Ended
	Sep. 30, 2017
Banking and Thrift [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	Actual capital amounts and ratios for the Company and its bank subsidiary, as of September 30, 2017 and December 31, 2016 are presented in the following tables: Actual Adequately Capitalized Basel III Phase-In Schedule Adequately Capitalized Basel III Fully Phased-In Well Capitalized (1) Amount Ratio Amount Ratio Amount Ratio Amount Ratio September 30, 2017 Total risk-based capital: Consolidated $ 1,100,588 12.76 % $ 797,584 9.25 % $ 905,365 10.50 % $ 862,253 10.00 % FIB 1,097,287 12.78 793,974 9.25 901,268 10.50 858,350 10.00 Tier 1 risk-based capital: Consolidated 1,026,016 11.90 625,133 7.25 732,915 8.50 689,802 8.00 FIB 1,022,715 11.91 622,304 7.25 729,598 8.50 686,680 8.00 Common equity tier 1 risk-based capital: Consolidated 949,821 11.02 495,795 5.75 603,577 7.00 560,464 6.50 FIB 1,022,715 11.91 493,551 5.75 600,845 7.00 557,928 6.50 Leverage capital ratio: Consolidated 1,026,016 8.71 471,221 4.00 471,221 4.00 589,026 5.00 FIB 1,022,715 8.72 469,107 4.00 469,107 4.00 586,384 5.00 Actual Adequately Capitalized Basel III Phase-In Schedule Adequately Capitalized Basel III Fully Phased-In Well Capitalized (1) Amount Ratio Amount Ratio Amount Ratio Amount Ratio December 31, 2016 Total risk-based capital: Consolidated $ 974,488 15.13 % $ 555,665 8.63 % $ 676,070 10.50 % $ 643,876 10.00 % FIB 841,967 13.13 553,459 8.63 673,386 10.50 641,320 10.00 Tier 1 risk-based capital: Consolidated 894,273 13.89 426,890 6.63 547,295 8.50 $ 515,101 8.00 FIB 765,753 11.94 425,195 6.63 545,122 8.50 513,056 8.00 Common equity tier 1 risk-based capital: Consolidated 814,273 12.65 330,308 5.13 450,713 7.00 $ 418,519 6.50 FIB 765,753 11.94 328,997 5.13 448,924 7.00 416,858 6.50 Leverage capital ratio: Consolidated 894,273 10.11 353,838 4.00 353,838 4.00 $ 442,297 5.00 FIB 765,753 8.69 352,283 4.00 352,283 4.00 440,353 5.00 (1) The ratios for the well capitalized requirement are only applicable to FIB. However, the Company manages its capital position as if the requirement applies to the consolidated entity and has presented the ratios as if they also applied on a consolidated basis.

Other Comprehensive Income_Lo35

Other Comprehensive Income/Loss (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Schedule of Comprehensive Income (Loss)	The gross amounts of each component of other comprehensive income and the related tax effects are as follows: Pre-tax Tax Expense (Benefit) Net of Tax Three Months Ended September 30, 2017 2016 2017 2016 2017 2016 Investment securities available-for sale: Change in net unrealized gains during period $ (1,812 ) $ (3,430 ) $ (845 ) $ (1,359 ) $ (967 ) $ (2,071 ) Reclassification adjustment for net gains included in net income (771 ) (225 ) (360 ) (89 ) (411 ) (136 ) Change in unamortized loss on available- for-sale securities transferred into held-to- maturity 465 490 217 209 248 281 Unrealized (gain) loss on derivatives (658 ) 512 (307 ) 195 (351 ) 317 Reclassification adjustment for derivatives net (gains) losses included in income 1,128 — 526 — 602 — Defined benefits post-retirement benefit plan: Change in net actuarial (gain) loss (176 ) 15 (82 ) 6 (94 ) 9 Total other comprehensive income $ (1,824 ) $ (2,638 ) $ (851 ) $ (1,038 ) $ (973 ) $ (1,600 ) Pre-tax Tax Expense (Benefit) Net of Tax Nine Months Ended September 30, 2017 2016 2017 2016 2017 2016 Investment securities available-for sale: Change in net unrealized gains during period $ 15,553 $ 15,241 $ 6,135 $ 5,963 $ 9,418 $ 9,278 Reclassification adjustment for net gains included in net income (778 ) (312 ) (307 ) (123 ) (471 ) (189 ) Change in unamortized loss on available- for-sale securities transferred into held-to- maturity 1,394 1,394 550 549 844 845 Unrealized loss on derivatives (1,095 ) (2,490 ) (432 ) (946 ) (663 ) (1,544 ) Reclassification adjustment for derivatives net (gains) losses included in income 1,128 — 445 — 683 — Defined benefits post-retirement benefit plan: Change in net actuarial loss (1,090 ) 43 (430 ) 17 (660 ) 26 Total other comprehensive income $ 15,112 $ 13,876 $ 5,961 $ 5,460 $ 9,151 $ 8,416
Schedule of Accumulated Other Comprehensive Income (Loss)	The components of accumulated other comprehensive loss, net of related tax effects, are as follows: September 30, December 31, Net unrealized gain (loss) on investment securities available-for-sale $ (353 ) $ (10,143 ) Net unrealized gain (loss) on derivatives — (23 ) Net actuarial gain (loss) on defined benefit post-retirement benefit plans 1,376 2,038 Net accumulated other comprehensive gain (loss) $ 1,023 $ (8,128 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis	Financial assets and financial liabilities measured at fair value on a recurring basis are as follows: Fair Value Measurements at Reporting Date Using As of September 30, 2017 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment securities available-for-sale: U.S. Treasury Notes $ 3,205 $ — $ 3,205 $ — Obligations of U.S. government agencies 505,578 — 505,578 — U.S. agencies mortgage-backed securities & collateralized mortgage obligations 1,435,238 — 1,435,238 — Private mortgage-backed securities 97,838 — 97,838 — Corporate securities 66,878 — 66,878 Other investments 2,960 — 2,960 — Loans held for sale 49,729 — 49,729 — Derivative assets: Interest rate swap contracts 8,764 — 8,764 — Interest rate lock commitments 1,627 — 1,627 — Forward loan sale contracts 330 — 330 — Derivative liabilities: Interest rate swap contracts 9,099 — 9,099 — Deferred compensation plan assets 11,632 — 11,632 — Deferred compensation plan liabilities 11,632 — 11,632 — Fair Value Measurements at Reporting Date Using As of December 31, 2016 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Investment securities available-for-sale: U.S. Treasury notes $ 3,612 $ — $ 3,612 $ — Obligations of U.S. government agencies 391,297 — 391,297 — U.S. agencies mortgage-backed securities & collateralized mortgage obligations 1,213,701 — 1,213,701 — Private mortgage-backed securities 116 — 116 — Other investments 2,972 — 2,972 — Loans held for sale 61,794 — 61,794 — Derivative assets: Interest rate swap contracts 1,332 — 1,332 — Interest rate lock commitments 1,131 — 1,131 — Forward loan sales contracts 286 — 286 — Derivative liabilities Interest rate swap contracts 1,314 — 1,314 — Deferred compensation plan assets 10,627 — 10,627 — Deferred compensation plan liabilities 10,627 — 10,627 —
Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Non-Recurring Basis	The following table presents information about the Company’s assets and liabilities measured at fair value on a non-recurring basis: Fair Value Measurements at Reporting Date Using As of September 30, 2017 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Impaired loans $ 34,489 $ — $ — $ 34,489 Other real estate owned 1,578 — — 1,578 Long-lived assets to be disposed of by sale 356 — — 356 Fair Value Measurements at Reporting Date Using As of December 31, 2016 Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Impaired loans $ 39,344 $ — $ — $ 39,344 Other real estate owned 2,110 — — 2,110 Long-lived assets to be disposed of by sale 1,335 — — 1,335
Fair Value Inputs, Assets, Quantitative Information	The following table presents additional quantitative information about assets measured at fair value on a non-recurring basis and for which the Company has utilized Level 3 inputs to determine fair values: Fair Value As of September 30, 2017 December 31, 2016 Valuation Technique Unobservable Inputs Range (Weighted Average) Impaired loans $ 34,489 $ 39,344 Appraisal Appraisal adjustment 0% - 66% (31%) Other real estate owned 1,578 2,110 Appraisal Appraisal adjustment 8% - 96% (18%) Long-lived assets to be disposed of by sale 356 1,335 Appraisal Appraisal adjustment 0% - 9% (6%)
Fair Value, by Balance Sheet Grouping	The estimated fair values of financial instruments that are reported in the Company's consolidated balance sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, are as follows: Fair Value Measurements at Reporting Date Using As of September 30, 2017 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 882,834 $ 882,834 $ 882,834 $ — $ — Investment securities available-for-sale 2,111,697 2,111,697 — 2,111,697 — Investment securities held-to-maturity 505,985 510,405 — 510,405 — Accrued interest receivable 40,621 40,621 — 40,621 — Mortgage servicing rights, net 24,372 38,142 — 38,142 — Loans held for sale 49,729 49,729 — 49,729 — Net loans held for investment 7,427,815 7,163,825 — 7,129,336 34,489 Derivative assets 10,721 10,721 — 10,721 — Deferred compensation plan assets 11,632 11,632 — 11,632 — Total financial assets $ 11,065,406 $ 10,819,606 $ 882,834 $ 9,902,283 $ 34,489 Financial liabilities: Total deposits, excluding time deposits $ 8,751,295 $ 8,751,295 $ 8,751,295 $ — $ — Time deposits 1,182,173 1,172,783 — 1,172,783 — Securities sold under repurchase agreements 635,288 635,288 — 635,288 — Other borrowed funds 30,008 30,008 — 30,008 — Accrued interest payable 5,648 5,648 — 5,648 — Long-term debt 8,039 8,266 — 8,266 — Subordinated debentures held by subsidiary trusts 82,477 92,303 — 92,303 — Derivative liabilities 9,099 9,099 — 9,099 — Deferred compensation plan liabilities 11,632 11,632 — 11,632 — Total financial liabilities $ 10,715,659 $ 10,716,322 $ 8,751,295 $ 1,965,027 $ — Fair Value Measurements at Reporting Date Using As of December 31, 2016 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial assets: Cash and cash equivalents $ 782,023 $ 782,023 $ 782,023 $ — $ — Investment securities available-for-sale 1,611,698 1,611,698 — 1,611,698 — Investment securities held-to-maturity 512,770 513,273 — 513,273 — Accrued interest receivable 29,852 29,852 — 29,852 — Mortgage servicing rights, net 18,457 35,656 — 35,656 — Loans held for sale 61,794 61,794 — 61,794 — Net loans held for investment 5,340,536 5,248,127 — 5,208,783 39,344 Derivative assets 2,749 2,749 — 2,749 — Deferred compensation plan assets 10,627 10,627 — 10,627 — Total financial assets $ 8,370,506 $ 8,295,799 $ 782,023 $ 7,474,432 $ 39,344 Financial liabilities: Total deposits, excluding time deposits $ 6,324,512 $ 6,324,512 $ 6,324,512 $ — $ — Time deposits 1,051,598 1,044,670 — 1,044,670 — Securities sold under repurchase agreements 537,556 537,556 — 537,556 — Other borrowed funds 6 6 — 6 — Accrued interest payable 5,421 5,421 — 5,421 — Long-term debt 27,970 27,477 — 27,477 — Subordinated debentures held by subsidiary trusts 82,477 73,554 — 73,554 — Derivative liabilities 1,314 1,314 — 1,314 — Deferred compensation plan liabilities 10,627 10,627 — 10,627 — Total financial liabilities $ 8,041,481 $ 8,025,137 $ 6,324,512 $ 1,700,625 $ —

Acquisitions - Business Combin

Acquisitions - Business Combination (Narrative) (Details)	May 30, 2017USD ($)segment$ / sharesshares	Jun. 30, 2017USD ($)	Sep. 30, 2017USD ($)officeshares	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)officeshares	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Effective date of merger					May 30, 2017
Business acquisition cash conversion amount (in dollars per share) | $ / shares	$ 1.91
Number of shares issued in connection with Cascade merger | shares	11,300,000
Price per share of First Interstate Class A common stock (in dollars per share) | $ / shares	$ 34.30
Cash paid related to Cascade Options					$ 9,300,000
Cash paid for Cascade unvested restricted stock			$ 2,200,000		$ 2,200,000
Shares issued for Cascade unvested restricted stock | shares			168,000		168,000
Expense related to restricted awards excluded from consideration	$ 2,400,000
Restricted stock expense included in consideration					$ 5,500,000
Goodwill			$ 445,028,000		445,028,000		$ 212,820,000
Number of operating segments | segment	1
Established through acquisitions or provisional adjustments			19,000	$ 2,486,000	47,968,000	$ 2,486,000
Acquisition related expenses			$ 13,016,000	$ 1,197,000	23,854,000	$ 1,197,000
Acquisition-related costs					$ 19,700,000
Bank of the Cascades
Business Acquisition [Line Items]
Number of banking offices | office			46		46
Class A Common Stock
Business Acquisition [Line Items]
Number of shares issued in connection with Cascade merger | shares	11,252,750
Bank of the Cascades
Business Acquisition [Line Items]
Date of agreement and plan for merger with Cascade Bancorp					Nov. 17, 2016
Valuation allowance for deferred tax assets			$ 0		$ 0
Acquisition related expenses			$ 13,016,000		$ 23,854,000
Revenue reported by Cascade		$ 12,900,000
Net income reported by Cascade		$ 3,000,000
Bank of the Cascades | Class A Common Stock
Business Acquisition [Line Items]
Business acquisition conversion share rate | shares	0.14864
Bank of the Cascades | Core Deposits
Business Acquisition [Line Items]
Established through acquisitions or provisional adjustments	$ 48,000,000
Estimated useful lives of related deposits	10 years				10 years
Cascade Bank Acquisition, as Recorded by the Company
Business Acquisition [Line Items]
Cash paid by First Interstate in connection with merger	$ 155,029,000
Total consideration exchanged in connection with the merger	540,998,000
Goodwill	$ 232,208,000

Acquisitions - Schedule of Rec

Acquisitions - Schedule of Recognized Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands		May 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Class A common stock		$ 385,969
Goodwill			$ 445,028	$ 212,820
Cascade Bank Acquisition, as recorded by Cascade Bank
Business Acquisition [Line Items]
Cash and cash equivalents		246,804
Investment securities		476,733
Loans held for investment		2,112,077
Mortgage loans held for sale		10,253
Allowance for loan loss		(23,974)
Premises and equipment		46,554
Other real estate owned (OREO)		1,192
Core deposit intangible		0
Deferred tax assets		47,653
Other assets		98,570
Total assets acquired		3,015,862
Deposits		2,669,910
Accounts Payable and Accrued Expense		62,150
Total liabilities assumed		2,732,060
Net assets acquired		283,802
Cascade Bank Acquisition, Fair Value Adjustments
Business Acquisition [Line Items]
Cash and cash equivalents		0
Investment securities	[1]	4,876
Loans held for investment	[2]	(31,703)
Mortgage loans held for sale		6
Allowance for loan loss	[3]	23,974
Premises and equipment	[4]	178
Other real estate owned (OREO)		0
Core deposit intangible	[5]	47,968
Deferred tax assets	[6]	(21,661)
Other assets	[7]	1,136
Total assets acquired		24,774
Deposits	[8]	(934)
Accounts Payable and Accrued Expense	[9]	720
Total liabilities assumed		(214)
Net assets acquired		24,988
Cascade Bank Acquisition, as Recorded by the Company
Business Acquisition [Line Items]
Cash and cash equivalents		246,804
Investment securities		481,609
Loans held for investment		2,080,374
Mortgage loans held for sale		10,259
Allowance for loan loss		0
Premises and equipment		46,732
Other real estate owned (OREO)		1,192
Core deposit intangible		47,968
Deferred tax assets		25,992
Other assets		99,706
Total assets acquired		3,040,636
Deposits		2,668,976
Accounts Payable and Accrued Expense		62,870
Total liabilities assumed		2,731,846
Net assets acquired		308,790
Cash		155,029
Class A common stock		385,969
Total consideration paid		540,998
Goodwill		$ 232,208
[1]	Write up of the book value of investments to their estimated fair values on the date of acquisition based upon quotes obtained from an independent third party pricing service.
[2]	Write down of the book value of loans to their estimated fair values. Shared National Credits (SNC) were recorded at quoted sales prices where available. The fair value of the remaining loans was estimated using cash flow projections based on the remaining maturity and repricing terms, adjusted for estimated future credit losses and prepayments and discounted to present value using a risk-adjusted market rate for similar loans. The fair value of collateral dependent loans acquired with deteriorated credit quality was estimated based on the Company's analysis of the fair value of each loan's underlying collateral, discounted using market-derived rates of return with consideration given to the period of time and costs associated with foreclosure and disposition of the collateral.
[3]	Adjustment to remove the Cascade allowance for loan losses at acquisition date, as the credit risk is accounted for in the fair value adjustment for loans receivable described in (2) above.
[4]	Write up of the book value of premises and equipment to their estimated fair values on the date of acquisition based upon appraisals obtained from an independent third party appraiser or broker's opinion of value.
[5]	Adjustment represents the value of the core deposit base assumed in the acquisition based upon valuation from an independent accounting and advisory firm.
[6]	Adjustment consists of the write-off of pre-existing deferred tax assets as a result of the acquisition.
[7]	Adjustment consists of various other assets recorded as a result of the acquisition, including mortgage servicing rights, SBA servicing rights, and favorable leases offset by reductions to the fair value of other items.
[8]	Decrease in book value of time deposits to their estimated fair values based upon interest rates of similar time deposits with similar terms on the date of acquisition based upon valuation from an independent accounting and advisory firm.
[9]	Increase in fair value due to credit card incentive program, unfavorable leases, write-off of balance sheet reserve, and swap liability offset.

Acquisitions - Summary of Pre-

Acquisitions - Summary of Pre-tax Merger Related Costs (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Acquisition [Line Items]
Employee Expenses	$ 34,662,000	$ 26,908,000	$ 88,440,000	$ 79,755,000
Total Acquisition Related Expenses	13,016,000	$ 1,197,000	23,854,000	$ 1,197,000
Business Combinations, Legal and Professional Fees	0		6,542,000
Bank of the Cascades
Business Acquisition [Line Items]
Legal and Professional Fees	2,498,000		8,995,000
Employee Expenses	1,755,000		5,041,000
Technology Conversion and Contract Termination	7,090,000		7,779,000
Other	1,673,000		2,039,000
Total Acquisition Related Expenses	$ 13,016,000		$ 23,854,000

Acquisitions - Schedule of Acq

Acquisitions - Schedule of Acquired loans with credit impairment (Details) $ in Thousands	May 30, 2017USD ($)
Business Combinations [Abstract]
Contractually required principal and interest payments	$ 48,041
Contractual cash flows not expected to be collected (non-accretable discount)	23,376
Cash flows expected to be collected	24,665
Interest component of cash flows expected to be collected (accretable discount)	1,901
Fair value of acquired credit-impaired loans	$ 22,764

Acquisitions - Schedule of A41

Acquisitions - Schedule of Acquired Loans not Deemed to Have Credit Impairment (Details) $ in Thousands	May 30, 2017USD ($)
Business Combinations [Abstract]
Contractually required principal and interest payments	$ 2,098,452
Contractual cash flows not expected to be collected due to projected prepayment	23,387
Fair value at acquisition	$ 2,067,869

Acquisitions - Business Acquis

Acquisitions - Business Acquisition, Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Combinations [Abstract]
Interest income	$ 108,765	$ 99,288	$ 312,091	$ 289,060
Non-interest income	38,274	39,811	116,171	114,881
Total revenues	147,039	139,099	428,262	403,941
Net income	$ 34,903	$ 28,769	$ 94,017	$ 44,317
EPS - basic (in dollars per share)	$ 0.52	$ 0.52	$ 1.55	$ 0.79
EPS - diluted (in dollars per share)	$ 0.51	$ 0.51	$ 1.53	$ 0.79

Goodwill and Intangibles - Narr

Goodwill and Intangibles - Narrative (Details) - USD ($)	May 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill		$ 445,028,000	$ 212,820,000
Impairment of goodwill		$ 0
Cascade Bancorp
Goodwill [Line Items]
Goodwill	$ 232,200,000
Core Deposits | Bank of the Cascades
Goodwill [Line Items]
Weighted average useful lives of related deposits	10 years	10 years

Goodwill and Intangibles - Sche

Goodwill and Intangibles - Schedule of Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Goodwill [Roll Forward]
CDI, net, beginning of period	$ 52,837	$ 8,935	$ 9,648	$ 10,589
Established through acquisitions or provisional adjustments	19	2,486	47,968	2,486
Reductions due to sale of accounts	0	0	(3,068)	0
CDI current period amortization	(1,885)	(875)	(3,577)	(2,529)
Total CDI, net, at September 30	$ 50,971	$ 10,546	$ 50,971	$ 10,546

Goodwill and Intangibles - Sc45

Goodwill and Intangibles - Schedule of Future Amortization Expense (Details) $ in Thousands	Sep. 30, 2017USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2017 remaining	$ 1,298
2,018	5,093
2,019	4,994
2,020	4,872
2,021	4,729
Thereafter	$ 29,985

Investment Securities - Amorti

Investment Securities - Amortized Cost and Approximate Fair Values of Investment Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available-for-Sale:
Amortized Cost	$ 2,110,200	$ 1,624,976
Gross Unrealized Gains	9,616	6,782
Gross Unrealized Losses	(8,119)	(20,060)
Estimated Fair Value	2,111,697	1,611,698
Held-to-Maturity:
Amortized Cost	505,985	512,770
Gross Unrealized Gains	14,767	10,667
Gross Unrealized Losses	(10,347)	(10,164)
Estimated Fair Value	510,405	513,273
U.S. Treasury notes
Available-for-Sale:
Amortized Cost	3,206	3,608
Gross Unrealized Gains	1	5
Gross Unrealized Losses	(2)	(1)
Estimated Fair Value	3,205	3,612
Obligations of U.S. government agencies
Available-for-Sale:
Amortized Cost	508,449	397,411
Gross Unrealized Gains	338	343
Gross Unrealized Losses	(3,209)	(6,457)
Estimated Fair Value	505,578	391,297
Held-to-Maturity:
Amortized Cost	19,737	19,737
Gross Unrealized Gains	43	0
Gross Unrealized Losses	(19)	(162)
Estimated Fair Value	19,761	19,575
U.S. agency residential mortgage-backed securities & collateralized mortgage obligations
Available-for-Sale:
Amortized Cost	1,431,125	1,220,890
Gross Unrealized Gains	8,829	6,412
Gross Unrealized Losses	(4,716)	(13,601)
Estimated Fair Value	1,435,238	1,213,701
Held-to-Maturity:
Amortized Cost	243,380	279,578
Gross Unrealized Gains	10,725	7,804
Gross Unrealized Losses	(10,172)	(9,249)
Estimated Fair Value	243,933	278,133
Private mortgage-backed securities
Available-for-Sale:
Amortized Cost	97,715	116
Gross Unrealized Gains	313	1
Gross Unrealized Losses	(190)	(1)
Estimated Fair Value	97,838	116
State, county and municipal securities
Held-to-Maturity:
Amortized Cost	180,981	160,192
Gross Unrealized Gains	3,726	2,723
Gross Unrealized Losses	(123)	(542)
Estimated Fair Value	184,584	162,373
Corporate securities
Available-for-Sale:
Amortized Cost	66,754
Gross Unrealized Gains	126
Gross Unrealized Losses	(2)
Estimated Fair Value	66,878
Held-to-Maturity:
Amortized Cost	61,704	53,032
Gross Unrealized Gains	272	139
Gross Unrealized Losses	(33)	(211)
Estimated Fair Value	61,943	52,960
Other investments
Available-for-Sale:
Amortized Cost	2,951	2,951
Gross Unrealized Gains	9	21
Gross Unrealized Losses	0	0
Estimated Fair Value	2,960	2,972
Other Investments
Held-to-Maturity:
Amortized Cost	183	231
Gross Unrealized Gains	1	1
Gross Unrealized Losses	0	0
Estimated Fair Value	$ 184	$ 232

Investment Securities - Realiz

Investment Securities - Realized Gains (Losses) on Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 1,072	$ 239	$ 1,079	$ 404
Gross realized losses	$ (301)	$ (14)	$ (301)	$ (92)

Investment Securities - Gross

Investment Securities - Gross Unrealized Losses and Fair Values of Investment Securities (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)security	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)security	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)security
Available-for-Sale:
Available-for-Sale, Less than 12 Months, Fair Value	$ 899,537,000		$ 899,537,000		$ 1,063,374,000
Available-for-sale, Less than 12 Months, Gross Unrealized Losses	(6,382,000)		(6,382,000)		(19,560,000)
Available-for-Sale, 12 Months or More, Fair Value	161,481,000		161,481,000		15,849,000
Available-for-Sale, 12 Months or More, Gross Unrealized Losses	(1,737,000)		(1,737,000)		(500,000)
Available-for-Sale, Total Fair Value	1,061,018,000		1,061,018,000		1,079,223,000
Available-for-Sale, Total Gross Unrealized Losses	(8,119,000)		(8,119,000)		(20,060,000)
Held-to-Maturity:
Held-to-Maturity, Less than 12 Months, Fair Value	77,857,000		77,857,000		203,424,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(8,930,000)		(8,930,000)		(8,879,000)
Held-to-Maturity, 12 Months or More, Fair Value	28,071,000		28,071,000		22,817,000
Held-to-Maturity, 12 Months or More, Gross Unrealized Losses	(1,417,000)		(1,417,000)		(1,285,000)
Held-to-Maturity, Total Fair Value	105,928,000		105,928,000		226,241,000
Held-to-Maturity, Total Gross Unrealized Losses	$ (10,347,000)		$ (10,347,000)		$ (10,164,000)
Investment securities in an unrealized loss position (securities) | security	358		358		396
Impairment loss	$ 0	$ 0	$ 0	$ 0
U.S. Treasury notes
Available-for-Sale:
Available-for-Sale, Less than 12 Months, Fair Value	2,201,000		2,201,000		$ 598,000
Available-for-sale, Less than 12 Months, Gross Unrealized Losses	(2,000)		(2,000)		(1,000)
Available-for-Sale, 12 Months or More, Fair Value	0		0		0
Available-for-Sale, 12 Months or More, Gross Unrealized Losses	0		0		0
Available-for-Sale, Total Fair Value	2,201,000		2,201,000		598,000
Available-for-Sale, Total Gross Unrealized Losses	(2,000)		(2,000)		(1,000)
Obligations of U.S. government agencies
Available-for-Sale:
Available-for-Sale, Less than 12 Months, Fair Value	303,060,000		303,060,000		316,511,000
Available-for-sale, Less than 12 Months, Gross Unrealized Losses	(2,458,000)		(2,458,000)		(6,457,000)
Available-for-Sale, 12 Months or More, Fair Value	86,718,000		86,718,000		0
Available-for-Sale, 12 Months or More, Gross Unrealized Losses	(751,000)		(751,000)		0
Available-for-Sale, Total Fair Value	389,778,000		389,778,000		316,511,000
Available-for-Sale, Total Gross Unrealized Losses	(3,209,000)		(3,209,000)		(6,457,000)
Held-to-Maturity:
Held-to-Maturity, Less than 12 Months, Fair Value	9,972,000		9,972,000		19,575,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(19,000)		(19,000)		(162,000)
Held-to-Maturity, 12 Months or More, Fair Value	0		0		0
Held-to-Maturity, 12 Months or More, Gross Unrealized Losses	0		0		0
Held-to-Maturity, Total Fair Value	9,972,000		9,972,000		19,575,000
Held-to-Maturity, Total Gross Unrealized Losses	(19,000)		(19,000)		(162,000)
U.S. agency residential mortgage-backed securities & collateralized mortgage obligations
Available-for-Sale:
Available-for-Sale, Less than 12 Months, Fair Value	556,771,000		556,771,000		746,265,000
Available-for-sale, Less than 12 Months, Gross Unrealized Losses	(3,731,000)		(3,731,000)		(13,102,000)
Available-for-Sale, 12 Months or More, Fair Value	74,732,000		74,732,000		15,801,000
Available-for-Sale, 12 Months or More, Gross Unrealized Losses	(985,000)		(985,000)		(499,000)
Available-for-Sale, Total Fair Value	631,503,000		631,503,000		762,066,000
Available-for-Sale, Total Gross Unrealized Losses	(4,716,000)		(4,716,000)		(13,601,000)
Held-to-Maturity:
Held-to-Maturity, Less than 12 Months, Fair Value	38,712,000		38,712,000		108,857,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(8,814,000)		(8,814,000)		(7,973,000)
Held-to-Maturity, 12 Months or More, Fair Value	18,846,000		18,846,000		19,986,000
Held-to-Maturity, 12 Months or More, Gross Unrealized Losses	(1,358,000)		(1,358,000)		(1,276,000)
Held-to-Maturity, Total Fair Value	57,558,000		57,558,000		128,843,000
Held-to-Maturity, Total Gross Unrealized Losses	(10,172,000)		(10,172,000)		(9,249,000)
Private mortgage-backed securities
Available-for-Sale:
Available-for-Sale, Less than 12 Months, Fair Value	30,518,000		30,518,000		0
Available-for-sale, Less than 12 Months, Gross Unrealized Losses	(189,000)		(189,000)		0
Available-for-Sale, 12 Months or More, Fair Value	31,000		31,000		48,000
Available-for-Sale, 12 Months or More, Gross Unrealized Losses	(1,000)		(1,000)		(1,000)
Available-for-Sale, Total Fair Value	30,549,000		30,549,000		48,000
Available-for-Sale, Total Gross Unrealized Losses	(190,000)		(190,000)		(1,000)
State, county and municipal securities
Held-to-Maturity:
Held-to-Maturity, Less than 12 Months, Fair Value	25,207,000		25,207,000		42,518,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	(97,000)		(97,000)		(533,000)
Held-to-Maturity, 12 Months or More, Fair Value	4,208,000		4,208,000		2,831,000
Held-to-Maturity, 12 Months or More, Gross Unrealized Losses	(26,000)		(26,000)		(9,000)
Held-to-Maturity, Total Fair Value	29,415,000		29,415,000		45,349,000
Held-to-Maturity, Total Gross Unrealized Losses	(123,000)		(123,000)		(542,000)
Corporate securities
Available-for-Sale:
Available-for-Sale, Less than 12 Months, Fair Value	6,987,000		6,987,000
Available-for-sale, Less than 12 Months, Gross Unrealized Losses	(2,000)		(2,000)
Available-for-Sale, 12 Months or More, Fair Value	0		0
Available-for-Sale, 12 Months or More, Gross Unrealized Losses	0		0
Available-for-Sale, Total Fair Value	6,987,000		6,987,000
Available-for-Sale, Total Gross Unrealized Losses	(2,000)		(2,000)
Held-to-Maturity:
Held-to-Maturity, Less than 12 Months, Fair Value	3,966,000		3,966,000		32,474,000
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses	0		0		(211,000)
Held-to-Maturity, 12 Months or More, Fair Value	5,017,000		5,017,000		0
Held-to-Maturity, 12 Months or More, Gross Unrealized Losses	(33,000)		(33,000)		0
Held-to-Maturity, Total Fair Value	8,983,000		8,983,000		32,474,000
Held-to-Maturity, Total Gross Unrealized Losses	$ (33,000)		$ (33,000)		$ (211,000)

Investment Securities - Maturi

Investment Securities - Maturities of Investment Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity
Available-for-Sale Amortized Cost, Within One Year	$ 375,199
Available-for-Sale Amortized Cost, After One Year but Within Five Years	1,287,854
Available-for-Sale Amortized Cost, After Five Years but Within Ten Years	278,782
Available-for-Sale Amortized Cost, After Ten Years	168,365
Amortized Cost	2,110,200	$ 1,624,976
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity
Available-for-Sale Estimated Fair Value, Within One Year	376,264
Available-for-Sale Estimated Fair Value, After One Year but Within Five Years	1,288,384
Available-for-Sale Estimated Fair Value, After Five Years but Within Ten Years	278,277
Available-for-Sale Estimated Fair Value, After Ten Years	168,772
Available-for-Sale, Estimated Fair Value	2,111,697	1,611,698
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount
Held-to-Maturity Amortized Cost, Within One Year	87,077
Held-to-Maturity Amortized Cost, After One Year but Within Five Years	264,417
Held-to-Maturity Amortized Cost, After Five Years but Within Ten Years	119,579
Held-to-Maturity Amortized Cost, After Ten Years	34,912
Amortized Cost	505,985	512,770
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity
Held-to-Maturity Estimated Fair Value, Within One Year	83,899
Held-to-Maturity Estimated Fair Value, After One Year but Within Five Years	272,442
Held-to-Maturity Estimated Fair Value, After Five Years but Within Ten Years	121,039
Held-to-Maturity Estimated Fair Value, After Ten Years	33,025
Held-to-Maturity, Estimated Fair Value	510,405	$ 513,273
Callable Within One Year
Available-for-sale Securities and Held-to-maturity Securities
Amortized cost of investment securities callable after one year but within five years	94,461
Fair value of investment securities callable after one year but within five years	$ 94,348

Loans - Schedule of Recorded I

Loans - Schedule of Recorded Investment in Past Due Loans by Class (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans	$ 7,502,387	$ 5,416,750
Mortgage loans held for sale	49,729	61,794
Total loans	7,552,116	5,478,544
Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	8,244	8,709
Current Loans	2,722,265	1,799,525
Non-accrual Loans	28,042	26,211
Total Loans	2,758,551	1,834,445
Land acquisition & development
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	2,214	1,264
Current Loans	345,234	202,223
Non-accrual Loans	4,720	5,025
Total Loans	352,168	208,512
Residential
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	3,313	1,195
Current Loans	230,533	146,245
Non-accrual Loans	205	456
Total Loans	234,051	147,896
Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
Current Loans	113,173	124,827
Non-accrual Loans	3,844	762
Total Loans	117,017	125,589
Total construction loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	5,527	2,459
Current Loans	688,940	473,295
Non-accrual Loans	8,769	6,243
Total Loans	703,236	481,997
Residential
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	15,002	5,968
Current Loans	1,478,314	1,014,990
Non-accrual Loans	5,711	6,435
Total Loans	1,499,027	1,027,393
Agricultural
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	9,860	628
Current Loans	148,219	165,293
Non-accrual Loans	2,218	4,327
Total Loans	160,297	170,248
Total real estate loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	38,633	17,764
Current Loans	5,037,738	3,453,103
Non-accrual Loans	44,740	43,216
Total Loans	5,121,111	3,514,083
Indirect consumer
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	8,846	11,466
Current Loans	778,434	740,163
Non-accrual Loans	1,505	780
Total Loans	788,785	752,409
Other consumer
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,957	1,724
Current Loans	175,275	146,006
Non-accrual Loans	358	357
Total Loans	177,590	148,087
Credit card
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	2,122	1,404
Current Loans	70,087	68,366
Non-accrual Loans	0	0
Total Loans	72,209	69,770
Total consumer loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	12,925	14,594
Current Loans	1,023,796	954,535
Non-accrual Loans	1,863	1,137
Total Loans	1,038,584	970,266
Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	5,479	4,632
Current Loans	1,154,196	767,878
Non-accrual Loans	26,532	25,432
Total Loans	1,186,207	797,942
Agricultural
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	2,144	1,894
Current Loans	149,192	127,956
Non-accrual Loans	1,345	3,008
Total Loans	152,681	132,858
Other, including overdrafts
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	312
Current Loans	3,804	1,289
Non-accrual Loans	0	0
Total Loans	3,804	1,601
Loans held for investment
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	59,181	39,196
Current Loans	7,368,726	5,304,761
Non-accrual Loans	74,480	72,793
Total Loans	7,502,387	5,416,750
Mortgage loans originated for sale
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
Current Loans	49,729	61,794
Non-accrual Loans	0	0
Mortgage loans held for sale	49,729	61,794
Total loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	59,181	39,196
Current Loans	7,418,455	5,366,555
Non-accrual Loans	74,480	72,793
Total loans	7,552,116	5,478,544
30 to 59 Days Past Due | Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	4,582	7,307
30 to 59 Days Past Due | Land acquisition & development
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,656	633
30 to 59 Days Past Due | Residential
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,245	931
30 to 59 Days Past Due | Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
30 to 59 Days Past Due | Total construction loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	2,901	1,564
30 to 59 Days Past Due | Residential
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	8,502	3,986
30 to 59 Days Past Due | Agricultural
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,327	341
30 to 59 Days Past Due | Total real estate loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	17,312	13,198
30 to 59 Days Past Due | Indirect consumer
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	6,840	8,425
30 to 59 Days Past Due | Other consumer
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,391	1,322
30 to 59 Days Past Due | Credit card
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,043	504
30 to 59 Days Past Due | Total consumer loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	9,274	10,251
30 to 59 Days Past Due | Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	3,308	3,171
30 to 59 Days Past Due | Agricultural
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,769	1,518
30 to 59 Days Past Due | Other, including overdrafts
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
30 to 59 Days Past Due | Loans held for investment
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	31,663	28,138
30 to 59 Days Past Due | Mortgage loans originated for sale
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
30 to 59 Days Past Due | Total loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	31,663	28,138
60 to 89 Days Past Due | Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,160	1,099
60 to 89 Days Past Due | Land acquisition & development
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	493	352
60 to 89 Days Past Due | Residential
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,598	264
60 to 89 Days Past Due | Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
60 to 89 Days Past Due | Total construction loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	2,091	616
60 to 89 Days Past Due | Residential
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	6,313	1,280
60 to 89 Days Past Due | Agricultural
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	8,533	287
60 to 89 Days Past Due | Total real estate loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	18,097	3,282
60 to 89 Days Past Due | Indirect consumer
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,659	2,329
60 to 89 Days Past Due | Other consumer
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	498	235
60 to 89 Days Past Due | Credit card
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	408	333
60 to 89 Days Past Due | Total consumer loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	2,565	2,897
60 to 89 Days Past Due | Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,094	727
60 to 89 Days Past Due | Agricultural
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	97	362
60 to 89 Days Past Due | Other, including overdrafts
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	1
60 to 89 Days Past Due | Loans held for investment
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	21,853	7,269
60 to 89 Days Past Due | Mortgage loans originated for sale
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
60 to 89 Days Past Due | Total loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	21,853	7,269
Equal to Greater than 90 Days Past Due | Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	2,502	303
Equal to Greater than 90 Days Past Due | Land acquisition & development
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	65	279
Equal to Greater than 90 Days Past Due | Residential
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	470	0
Equal to Greater than 90 Days Past Due | Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
Equal to Greater than 90 Days Past Due | Total construction loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	535	279
Equal to Greater than 90 Days Past Due | Residential
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	187	702
Equal to Greater than 90 Days Past Due | Agricultural
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
Equal to Greater than 90 Days Past Due | Total real estate loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	3,224	1,284
Equal to Greater than 90 Days Past Due | Indirect consumer
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	347	712
Equal to Greater than 90 Days Past Due | Other consumer
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	68	167
Equal to Greater than 90 Days Past Due | Credit card
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	671	567
Equal to Greater than 90 Days Past Due | Total consumer loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,086	1,446
Equal to Greater than 90 Days Past Due | Commercial
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	1,077	734
Equal to Greater than 90 Days Past Due | Agricultural
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	278	14
Equal to Greater than 90 Days Past Due | Other, including overdrafts
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	311
Equal to Greater than 90 Days Past Due | Loans held for investment
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	5,665	3,789
Equal to Greater than 90 Days Past Due | Mortgage loans originated for sale
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	0	0
Equal to Greater than 90 Days Past Due | Total loans
Loans and Leases Receivable Recorded Investment, Past Due [Line Items]
Total Loans 30 or More Days Past Due	$ 5,665	$ 3,789

Loans - Schedule of Outstandin

Loans - Schedule of Outstanding Unpaid Balances and Accrual Status of Loans Acquired with Credit Impairment (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities [Abstract]
Outstanding balance	$ 46,199	$ 38,505
Loans on accrual status	30,804	23,665
Total carrying value	$ 30,804	$ 23,665

Loans - Schedule of Changes in

Loans - Schedule of Changes in the Accretable Yield for Loans Acquired (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning Balance	$ 7,650	$ 5,905	$ 6,803	$ 6,713
Additions	167	1,114	2,096	1,114
Accretion income	(858)	(670)	(2,131)	(1,899)
Reductions due to exit events	(143)	(595)	(1,131)	(900)
Reclassifications from nonaccretable differences	498	729	1,677	1,455
Ending Balance	7,314	6,483	7,314	6,483
Interest Income on Non-Accrual Loans if Accrued	$ 946	$ 820	$ 1,814	$ 2,492

Loans - Schedule of Recorded53

Loans - Schedule of Recorded Investment in Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	$ 114,329		$ 114,329		$ 132,785
Recorded Investment With No Allowance	49,502		49,502		57,992
Recorded Investment With Allowance	40,946		40,946		46,699
Total Recorded Investment	90,448		90,448		104,691
Related Allowance	13,903		13,903		13,954
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	93,841	$ 81,974	97,573	$ 82,798
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	108	192	506	414
Interest Income on Impaired Loans If Interest Had Been Accrued	946	993	1,814	2,994
Commercial
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	47,934		47,934		57,017
Recorded Investment With No Allowance	21,558		21,558		24,410
Recorded Investment With Allowance	16,035		16,035		21,420
Total Recorded Investment	37,593		37,593		45,830
Related Allowance	3,947		3,947		2,847
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	40,362	33,408	41,712	35,572
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	54	100	281	241
Land acquisition & development
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	11,290		11,290		12,084
Recorded Investment With No Allowance	3,694		3,694		4,330
Recorded Investment With Allowance	1,714		1,714		1,813
Total Recorded Investment	5,408		5,408		6,143
Related Allowance	711		711		826
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	5,383	6,797	5,776	6,992
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	2	13	10	32
Residential
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	310		310		1,555
Recorded Investment With No Allowance	205		205		219
Recorded Investment With Allowance	0		0		619
Total Recorded Investment	205		205		838
Related Allowance	0		0		1
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	207	274	522	279
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	0	0	0	0
Commercial
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	4,725		4,725		4,786
Recorded Investment With No Allowance	417		417		3,940
Recorded Investment With Allowance	3,537		3,537		647
Total Recorded Investment	3,954		3,954		4,587
Related Allowance	2,148		2,148		657
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	4,192	1,055	4,271	1,007
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	1	1	45	3
Total construction loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	16,325		16,325		18,425
Recorded Investment With No Allowance	4,316		4,316		8,489
Recorded Investment With Allowance	5,251		5,251		3,079
Total Recorded Investment	9,567		9,567		11,568
Related Allowance	2,859		2,859		1,484
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	9,782	8,126	10,569	8,278
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	3	14	55	35
Residential
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	8,990		8,990		8,222
Recorded Investment With No Allowance	5,629		5,629		4,074
Recorded Investment With Allowance	2,122		2,122		2,470
Total Recorded Investment	7,751		7,751		6,544
Related Allowance	218		218		253
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	7,123	3,282	7,148	4,219
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	4	4	12	7
Agricultural
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	2,681		2,681		5,069
Recorded Investment With No Allowance	2,425		2,425		4,509
Recorded Investment With Allowance	156		156		181
Total Recorded Investment	2,581		2,581		4,690
Related Allowance	4		4		4
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	2,642	4,786	3,636	4,607
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	0	2	0	3
Total real estate loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	75,930		75,930		88,733
Recorded Investment With No Allowance	33,928		33,928		41,482
Recorded Investment With Allowance	23,564		23,564		27,150
Total Recorded Investment	57,492		57,492		68,632
Related Allowance	7,028		7,028		4,588
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	59,909	49,602	63,065	52,676
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	61	120	348	286
Total consumer loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	27		27
Recorded Investment With No Allowance	0		0
Recorded Investment With Allowance	25		25
Total Recorded Investment	25		25
Related Allowance	14		14
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	25	0	13	0
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	0		0	0
Commercial
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	36,787		36,787		40,314
Recorded Investment With No Allowance	14,623		14,623		13,230
Recorded Investment With Allowance	16,748		16,748		19,167
Total Recorded Investment	31,371		31,371		32,397
Related Allowance	6,426		6,426		9,254
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	31,637	30,123	31,884	27,781
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	47	72	156	128
Agricultural
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	1,585		1,585		3,738
Recorded Investment With No Allowance	951		951		3,280
Recorded Investment With Allowance	609		609		382
Total Recorded Investment	1,560		1,560		3,662
Related Allowance	435		435		$ 112
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	2,270	2,249	2,611	2,341
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized	$ 0	$ 0	$ 2	$ 0

Loans - Schedule of Loans Rene

Loans - Schedule of Loans Renegotiated in Troubled Debt Restructurings (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)note	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)note	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans renegotiated in troubled debt restructurings	$ 45,859,000		$ 45,859,000		$ 49,652,000
Loans renegotiated in troubled debt restructurings, non-accrual loans	34,997,000		34,997,000		27,309,000
Loans renegotiated in troubled debt restructurings, accrual loans	$ 10,862,000		$ 10,862,000		$ 22,343,000
Number of Notes | note	1		21
Loans restructured during period	$ 611,000		$ 11,308,000
Charge-offs directly related to modifying troubled debt restructurings	$ 0	$ 0	$ 0	$ 0
Number of notes under default | note	2		4
Balance of defaulted loans under trouble debt restructurings	$ 1,477,000		$ 7,235,000
Commitments to lend additional funds	0		0
Interest only period
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period	0		1,986,000
Extension of terms or maturity
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period	0		2,356,000
Interest Rate Adjustment Concession
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period	0		0
Other
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period	$ 611,000		$ 6,966,000
Commercial
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Number of Notes | note			5
Loans restructured during period			$ 2,772,000
Number of notes under default | note	1		2
Balance of defaulted loans under trouble debt restructurings	$ 177,000		$ 2,407,000
Commercial | Interest only period
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period			1,475,000
Commercial | Extension of terms or maturity
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period			388,000
Commercial | Interest Rate Adjustment Concession
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period			0
Commercial | Other
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period			$ 909,000
Commercial
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Number of Notes | note	1		16
Loans restructured during period	$ 611,000		$ 8,536,000
Number of notes under default | note	1		1
Balance of defaulted loans under trouble debt restructurings	$ 1,300,000		$ 1,300,000
Commercial | Interest only period
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period	0		511,000
Commercial | Extension of terms or maturity
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period	0		1,968,000
Commercial | Interest Rate Adjustment Concession
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period	0		0
Commercial | Other
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Loans restructured during period	$ 611,000		$ 6,057,000
Commercial
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Number of notes under default | note	0		1
Balance of defaulted loans under trouble debt restructurings	$ 0		$ 3,528,000

Loans - Schedule of Recorded55

Loans - Schedule of Recorded Investment in Criticized Loans by Class and Credit Quality Indicator (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	$ 7,502,387	$ 5,416,750
Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	2,758,551	1,834,445
Land acquisition & development
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	352,168	208,512
Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	234,051	147,896
Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	117,017	125,589
Total construction loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	703,236	481,997
Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	1,499,027	1,027,393
Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	160,297	170,248
Total real estate loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	5,121,111	3,514,083
Indirect consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	788,785	752,409
Other consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	177,590	148,087
Credit card
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	72,209	69,770
Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	1,038,584	970,266
Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	1,186,207	797,942
Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	152,681	132,858
Other Assets Especially Mentioned
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	147,121	163,581
Other Assets Especially Mentioned | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	79,921	85,292
Other Assets Especially Mentioned | Land acquisition & development
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	5,425	13,414
Other Assets Especially Mentioned | Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	3,690	412
Other Assets Especially Mentioned | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	2,564	1,555
Other Assets Especially Mentioned | Total construction loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	11,679	15,381
Other Assets Especially Mentioned | Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	4,607	5,038
Other Assets Especially Mentioned | Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	1,212	3,831
Other Assets Especially Mentioned | Total real estate loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	97,419	109,542
Other Assets Especially Mentioned | Indirect consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	660	778
Other Assets Especially Mentioned | Other consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	458	681
Other Assets Especially Mentioned | Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	1,118	1,459
Other Assets Especially Mentioned | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	43,365	46,402
Other Assets Especially Mentioned | Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	5,219	6,178
Substandard
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	239,326	172,325
Substandard | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	107,791	85,293
Substandard | Land acquisition & development
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	13,818	6,214
Substandard | Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	2,201	1,621
Substandard | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	3,842	6,344
Substandard | Total construction loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	19,861	14,179
Substandard | Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	11,664	12,472
Substandard | Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	23,574	17,813
Substandard | Total real estate loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	162,890	129,757
Substandard | Indirect consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	2,116	1,527
Substandard | Other consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	849	1,036
Substandard | Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	2,965	2,563
Substandard | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	61,612	29,281
Substandard | Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	11,859	10,724
Doubtful
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	36,142	36,336
Doubtful | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	12,025	10,842
Doubtful | Land acquisition & development
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	1,597	1,401
Doubtful | Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	0	656
Doubtful | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	3,747	664
Doubtful | Total construction loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	5,344	2,721
Doubtful | Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	1,039	764
Doubtful | Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	0	0
Doubtful | Total real estate loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	18,408	14,327
Doubtful | Indirect consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	120	101
Doubtful | Other consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	140	264
Doubtful | Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	260	365
Doubtful | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	16,495	21,240
Doubtful | Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	979	404
Total Criticized Loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	422,589	372,242
Total Criticized Loans | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	199,737	181,427
Total Criticized Loans | Land acquisition & development
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	20,840	21,029
Total Criticized Loans | Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	5,891	2,689
Total Criticized Loans | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	10,153	8,563
Total Criticized Loans | Total construction loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	36,884	32,281
Total Criticized Loans | Residential
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	17,310	18,274
Total Criticized Loans | Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	24,786	21,644
Total Criticized Loans | Total real estate loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	278,717	253,626
Total Criticized Loans | Indirect consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	2,896	2,406
Total Criticized Loans | Other consumer
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	1,447	1,981
Total Criticized Loans | Total consumer loans
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	4,343	4,387
Total Criticized Loans | Commercial
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	121,472	96,923
Total Criticized Loans | Agricultural
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Loans held for investment	$ 18,057	$ 17,306

Allowance for Loan Losses - Sc

Allowance for Loan Losses - Schedule of Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 75,701	$ 80,340	$ 76,214	$ 76,817
Provision charged to operating expense	3,443	2,363	7,528	8,913
Less loans charged-off	(7,460)	(3,115)	(15,622)	(10,858)
Add back recoveries of loans previously charged-off	2,888	1,647	6,452	6,363
Ending balance	74,572	81,235	74,572	81,235
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Loans individually evaluated for impairment					$ 13,903	$ 13,954
Loans collectively evaluated for impairment					60,669	62,260
Allowance for loan losses	75,701	80,340	76,214	76,817	74,572	76,214
Loans held for investment:
Individually evaluated for impairment					90,448	104,691
Individually evaluated for impairment					7,411,939	5,312,059
Total loans					7,502,387	5,416,750
Allowance for credit losses due to subsequent impairment					727	427
Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	33,498	32,281	28,625	52,296
Provision charged to operating expense	(690)	(352)	4,775	(20,492)
Less loans charged-off	(1,695)	(379)	(2,938)	(2,824)
Add back recoveries of loans previously charged-off	613	221	1,264	2,791
Ending balance	31,726	31,771	31,726	31,771
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Loans individually evaluated for impairment					7,028	4,588
Loans collectively evaluated for impairment					24,698	24,037
Allowance for loan losses	33,498	32,281	28,625	52,296	31,726	28,625
Loans held for investment:
Individually evaluated for impairment					57,492	68,632
Individually evaluated for impairment					5,063,619	3,445,451
Total loans					5,121,111	3,514,083
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	7,554	6,315	7,711	5,144
Provision charged to operating expense	2,620	2,395	5,157	5,747
Less loans charged-off	(3,115)	(2,157)	(8,123)	(5,761)
Add back recoveries of loans previously charged-off	962	742	3,276	2,165
Ending balance	8,021	7,295	8,021	7,295
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Loans individually evaluated for impairment					14	0
Loans collectively evaluated for impairment					8,007	7,711
Allowance for loan losses	7,554	6,315	7,711	5,144	8,021	7,711
Loans held for investment:
Individually evaluated for impairment					25	0
Individually evaluated for impairment					1,038,559	970,266
Total loans					1,038,584	970,266
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	33,124	39,995	38,092	18,775
Provision charged to operating expense	1,530	265	(2,145)	22,268
Less loans charged-off	(2,609)	(579)	(4,450)	(2,085)
Add back recoveries of loans previously charged-off	1,313	680	1,861	1,403
Ending balance	33,358	40,361	33,358	40,361
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Loans individually evaluated for impairment					6,426	9,254
Loans collectively evaluated for impairment					26,932	28,838
Allowance for loan losses	33,124	39,995	38,092	18,775	33,358	38,092
Loans held for investment:
Individually evaluated for impairment					31,371	32,397
Individually evaluated for impairment					1,154,836	765,545
Total loans					1,186,207	797,942
Agriculture
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,525	1,749	1,786	602
Provision charged to operating expense	(17)	55	(259)	1,390
Less loans charged-off	(41)	0	(111)	(188)
Add back recoveries of loans previously charged-off	0	4	51	4
Ending balance	1,467	1,808	1,467	1,808
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Loans individually evaluated for impairment					435	112
Loans collectively evaluated for impairment					1,032	1,674
Allowance for loan losses	1,525	1,749	1,786	602	1,467	1,786
Loans held for investment:
Individually evaluated for impairment					1,560	3,662
Individually evaluated for impairment					151,121	129,196
Total loans					152,681	132,858
Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0	0	0
Provision charged to operating expense	0	0	0	0
Less loans charged-off	0	0	0	0
Add back recoveries of loans previously charged-off	0	0	0	0
Ending balance	0	0	0	0
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Loans individually evaluated for impairment					0	0
Loans collectively evaluated for impairment					0	0
Allowance for loan losses	$ 0	$ 0	$ 0	$ 0	0	0
Loans held for investment:
Individually evaluated for impairment					0	0
Individually evaluated for impairment					3,804	1,601
Total loans					$ 3,804	$ 1,601

Other Real Estate Owned (Detail

Other Real Estate Owned (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Real Estate Acquired Through Foreclosure [Roll Forward]
Beginning balance	$ 11,286	$ 7,908	$ 10,019	$ 6,254
OREO acquired through acquisition	0	1,120	1,192	1,120
Additions	1,419	1,316	3,182	5,335
Valuation adjustments	(238)	0	(294)	(603)
Dispositions	(2,123)	(897)	(3,755)	(2,659)
Ending balance	10,344	$ 9,447	10,344	$ 9,447
Consumer mortgage loans collateralized by residential real estate property in the process of foreclosure	481		481		$ 0
Residential real estate
Real Estate Acquired Through Foreclosure [Roll Forward]
Beginning balance			2,282
Ending balance	$ 1,083		$ 1,083

Derivatives and Hedging Activ58

Derivatives and Hedging Activities - Schedule of Notional Amounts of Outstanding Derivative Positions (Details) - USD ($)	Sep. 06, 2017	Sep. 30, 2017	Dec. 31, 2016	Sep. 22, 2015
Derivative [Line Items]
Derivative Asset, Notional Amount		$ 510,832,000	$ 253,851,000
Derivative Asset, Estimated Fair Value		10,721,000	2,749,000
Notional amount of terminated commitment		327,569,000	153,593,000	$ 100,000,000
Derivative Liabilities, Estimated Fair Value		$ 9,099,000	1,314,000
Interest rate swap designated as a cash flow hedge, inception date		Sep. 22, 2015
Interest rate swap designated as a cash flow hedge, fixed interest rate				1.94%
Interest rate swap contracts
Derivative [Line Items]
Payment to terminate interest rate swap	$ 1,100,000
Not Designated as Hedging Instrument | Interest rate swap contracts
Derivative [Line Items]
Derivative Asset, Notional Amount		$ 327,569,000	53,593,000
Derivative Asset, Estimated Fair Value		8,764,000	1,332,000
Notional amount of terminated commitment		327,569,000	53,593,000
Derivative Liabilities, Estimated Fair Value		9,099,000	1,281,000
Not Designated as Hedging Instrument | Interest rate lock commitments
Derivative [Line Items]
Derivative Asset, Notional Amount		78,720,000	73,422,000
Derivative Asset, Estimated Fair Value		1,627,000	1,131,000
Not Designated as Hedging Instrument | Forward loan sales contracts
Derivative [Line Items]
Derivative Asset, Notional Amount		104,543,000	126,836,000
Derivative Asset, Estimated Fair Value		330,000	286,000
Designated as Hedging Instrument | Interest rate swap contracts
Derivative [Line Items]
Notional amount of terminated commitment		0	100,000,000
Derivative Liabilities, Estimated Fair Value		$ 0	$ 33,000

Derivatives and Hedging Activ59

Derivatives and Hedging Activities - Offsetting Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative Asset, Gross Amounts Recognized	$ 10,721	$ 2,749
Derivative Asset, Gross Amounts Offset in the Balance Sheet	0	0
Derivative Asset, Net Amounts in the Balance Sheet	10,721	2,749
Derivative Asset, Financial Instruments	1,530	479
Derivative Asset, Fair Value of Financial Collateral in the Balance Sheet	0	0
Derivative Asset, Net Amount	9,191	2,270
Total assets, Gross Amounts Recognized	10,721	2,749
Total assets, Gross Amounts Offset in the Balance Sheet	0	0
Total assets, Net Amounts in the Balance Sheet	10,721	2,749
Total assets, Financial Instruments	1,530	479
Total assets, Fair Value of Financial Collateral in the Balance Sheet	0	0
Total assets, Net Amount	9,191	2,270
Derivative liability, Gross Amounts Recognized	9,099	1,314
Derivative liability, Gross Amounts Offset in the Balance Sheet	0	0
Derivative liability, Net Amounts in the Balance Sheet	9,099	1,314
Derivative liability, Financial Instruments	1,530	479
Derivative liability, Fair Value of Financial Collateral in the Balance Sheet	7,569	0
Derivative liability, Net Amount	0	835
Repurchase agreements, Gross Amounts Recognized	635,288	537,556
Repurchase agreements, Gross Amounts Offset in the Balance Sheet	0	0
Repurchase agreements, Net Amounts in the Balance Sheet	635,288	537,556
Repurchase agreements, Financial Instruments	0	0
Repurchase agreements, Fair Value of Financial Collateral in the Balance Sheet	635,288	537,556
Repurchase agreements, Net Amount	0	0
Total liabilities, Gross Amounts Recognized	644,387	538,870
Total liabilities, Gross Amounts Offset in the Balance Sheet	0	0
Total liabilities, Net Amounts in the Balance Sheet	644,387	538,870
Total liabilities, Financial Instruments	1,530	479
Total liabilities, Fair Value of Financial Collateral in the Balance Sheet	642,857	537,556
Total liabilities, Net Amount	0	835
Interest Rate Swap
Derivative [Line Items]
Derivative Asset, Gross Amounts Recognized	8,764	1,332
Derivative Asset, Gross Amounts Offset in the Balance Sheet	0	0
Derivative Asset, Net Amounts in the Balance Sheet	8,764	1,332
Derivative Asset, Financial Instruments	1,530	479
Derivative Asset, Fair Value of Financial Collateral in the Balance Sheet	0	0
Derivative Asset, Net Amount	7,234	853
Mortgage Related Derivatives
Derivative [Line Items]
Derivative Asset, Gross Amounts Recognized	1,957	1,417
Derivative Asset, Gross Amounts Offset in the Balance Sheet	0	0
Derivative Asset, Net Amounts in the Balance Sheet	1,957	1,417
Derivative Asset, Financial Instruments	0	0
Derivative Asset, Fair Value of Financial Collateral in the Balance Sheet	0	0
Derivative Asset, Net Amount	$ 1,957	$ 1,417

Derivatives and Hedging Activ60

Derivatives and Hedging Activities - Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Designated as Hedging Instrument
Derivative [Line Items]
Amount of loss recognized in other comprehensive income (effective portion)	$ (658)	$ 512	$ (1,095)	$ (2,490)
Reclassification adjustment for derivatives net (gains) losses included in income	1,128	0	1,128	0
Not Designated as Hedging Instrument
Derivative [Line Items]
Amount of gain (loss) recognized in other non-interest income	24	(3)	(49)	(82)
Amount of net fee income recognized in other non-interest income	162	0	441	245
Amount of net gains recognized in mortgage banking revenues	$ 358	$ 752	$ 539	$ 1,970

Capital Stock (Details)

Capital Stock (Details) - USD ($) $ in Thousands	May 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Class of Stock [Line Items]
Number of shares issued as partial consideration for acquisition of Cascade Bancorp	11,300,000
Value of shares issued as partial consideration for acquisition of Cascade Bancorp	$ 385,969
Value of shares issued to board of directors		$ 522
Payment amount for repurchase of common stock		$ 938	$ 26,119
Class A Common Stock
Class of Stock [Line Items]
Common stock outstanding (in shares)		33,383,364		21,613,885
Number of shares issued as partial consideration for acquisition of Cascade Bancorp	11,252,750
Number of shares issued to board of directors		14,926
Stock repurchased and retired (in shares)		0	975,877
Payment amount for repurchase of common stock			$ 25,525
Remaining authorized repurchase amount under stock repurchase program (shares)		24,123
Class B Common Stock
Class of Stock [Line Items]
Common stock outstanding (in shares)		23,072,524		23,312,291

Earnings per Common Share - Co

Earnings per Common Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share, Basic and Diluted [Line Items]
Net income	$ 27,259	$ 25,193	$ 72,253	$ 70,871
Weighted average common shares outstanding for basic earnings per share computation	56,094,401	44,415,213	49,514,818	44,505,544
Dilutive effects of stock-based compensation	436,467	390,708	486,064	379,368
Weighted average common shares outstanding for diluted earnings per common share computation	56,530,868	44,805,921	50,000,882	44,884,912
Basic earnings per common share (in dollars per share)	$ 0.49	$ 0.57	$ 1.46	$ 1.59
Diluted earnings per common share (in dollars per share)	$ 0.48	$ 0.56	$ 1.45	$ 1.58
Unvested Restricted Stock
Earnings Per Share, Basic and Diluted [Line Items]
Anti-dilutive unvested time restricted stock	0	135	94,210	95,886
Restricted stock
Earnings Per Share, Basic and Diluted [Line Items]
Anti-dilutive unvested time restricted stock			174,696	218,556

Regulatory Capital - Schedule

Regulatory Capital - Schedule of Actual Capital Amounts and Ratios and Selected Minimum Regulatory Thresholds (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Total risk-based capital:
Actual Amount	$ 1,100,588	$ 974,488
Actual Ratio	12.76%	15.13%
Capital Required for Capital Adequacy under Basel III Phase-in Schedule	$ 797,584	$ 555,665
Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets	9.25%	8.63%
Capital Required for Capital Adequacy under Basel III Fully Phased-in	$ 905,365	$ 676,070
Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets	10.50%	10.50%
Well Capitalized Amount	$ 862,253	$ 643,876
Well Capitalized Ratio	10.00%	10.00%
Tier 1 risk-based capital:
Actual Amount	$ 1,026,016	$ 894,273
Actual Ratio	11.90%	13.89%
Tier One Risk Based Capital under Basel III Phase-in Schedule	$ 625,133	$ 426,890
Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets	7.25%	6.63%
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in	$ 732,915	$ 547,295
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets	8.50%	8.50%
Well Capitalized Amount	$ 689,802	$ 515,101
Well Capitalized Ratio	8.00%	8.00%
Common equity tier one risk-based capital:
Actual Amount	$ 949,821	$ 814,273
Actual Ratio	11.02%	12.65%
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule	$ 495,795	$ 330,308
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets	5.75%	5.13%
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in	$ 603,577	$ 450,713
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets	7.00%	7.00%
Well Capitalized Amount	$ 560,464	$ 418,519
Well Capitalized Ratio	6.50%	6.50%
Leverage capital ratio:
Actual Amount	$ 1,026,016	$ 894,273
Actual Ratio	8.71%	10.11%
Adequately Capitalized Amount	$ 471,221	$ 353,838
Adequately Capitalized Ratio	4.00%	4.00%
Well Capitalized Amount	$ 589,026	$ 442,297
Well Capitalized Ratio	5.00%	5.00%
FIB
Total risk-based capital:
Actual Amount	$ 1,097,287	$ 841,967
Actual Ratio	12.78%	13.13%
Capital Required for Capital Adequacy under Basel III Phase-in Schedule	$ 793,974	$ 553,459
Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets	9.25%	8.63%
Capital Required for Capital Adequacy under Basel III Fully Phased-in	$ 901,268	$ 673,386
Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets	10.50%	10.50%
Well Capitalized Amount	$ 858,350	$ 641,320
Well Capitalized Ratio	10.00%	10.00%
Tier 1 risk-based capital:
Actual Amount	$ 1,022,715	$ 765,753
Actual Ratio	11.91%	11.94%
Tier One Risk Based Capital under Basel III Phase-in Schedule	$ 622,304	$ 425,195
Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets	7.25%	6.63%
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in	$ 729,598	$ 545,122
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets	8.50%	8.50%
Well Capitalized Amount	$ 686,680	$ 513,056
Well Capitalized Ratio	8.00%	8.00%
Common equity tier one risk-based capital:
Actual Amount	$ 1,022,715	$ 765,753
Actual Ratio	11.91%	11.94%
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule	$ 493,551	$ 328,997
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets	5.75%	5.13%
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in	$ 600,845	$ 448,924
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets	7.00%	7.00%
Well Capitalized Amount	$ 557,928	$ 416,858
Well Capitalized Ratio	6.50%	6.50%
Leverage capital ratio:
Actual Amount	$ 1,022,715	$ 765,753
Actual Ratio	8.72%	8.69%
Adequately Capitalized Amount	$ 469,107	$ 352,283
Adequately Capitalized Ratio	4.00%	4.00%
Well Capitalized Amount	$ 586,384	$ 440,353
Well Capitalized Ratio	5.00%	5.00%

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016	Sep. 22, 2015
Loss Contingencies [Line Items]
Notional amount of terminated commitment	$ 327,569,000	$ 153,593,000	$ 100,000,000
Mortgage Loans Held for Sale
Loss Contingencies [Line Items]
Mortgage loans with recourse provision in effect	875,000
Construction Contracts
Loss Contingencies [Line Items]
Commitments under construction contracts	$ 731,000

Financial Instruments with Of65

Financial Instruments with Off-Balance Sheet Risk (Details) $ in Millions	Sep. 30, 2017USD ($)
Entity Information [Line Items]
Credit extension commitments	$ 2,100
Credit extension commitments beyond one year	721.7
Unused Credit Card Lines
Entity Information [Line Items]
Credit extension commitments	618.1
Standby Letters of Credit
Entity Information [Line Items]
Credit extension commitments	$ 52.6

Other Comprehensive Income_Lo66

Other Comprehensive Income/Loss - Schedule of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Investment securities available-for sale:
Change in net unrealized gain during period, pre-tax	$ (1,812)	$ (3,430)	$ 15,553	$ 15,241
Change in net unrealized gain during period, tax expense (benefit)	(845)	(1,359)	6,135	5,963
Change in net unrealized gain during period, net of tax	(967)	(2,071)	9,418	9,278
Reclassification adjustment for gains included in net income, pre-tax	(771)	(225)	(778)	(312)
Reclassification adjustment for gains included in net income, tax expense (benefit)	(360)	(89)	(307)	(123)
Reclassification adjustment for gains included in net income, net of tax	(411)	(136)	(471)	(189)
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity, pre-tax	465	490	1,394	1,394
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity, tax expense (benefit)	217	209	550	549
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity, net of tax	248	281	844	845
Unrealized (gain) loss on derivatives, pre-tax	(658)	512	(1,095)	(2,490)
Unrealized (gain) loss on derivatives, tax expense (benefit)	(307)	195	(432)	(946)
Unrealized (gain) loss on derivatives, net of tax	(351)	317	(663)	(1,544)
Reclassification adjustment for derivatives net (gains) losses included in income	1,128	0	1,128	0
Reclassification adjustment for derivatives net (gains) losses included in income, tax expense (benefit)	526	0	445	0
Reclassification adjustment for derivatives net (gains) losses included in income, net of tax	602	0	683	0
Defined benefits post-retirement benefit plan:
Change in net actuarial (gain) loss, pre-tax	(176)	15	(1,090)	43
Change in net actuarial (gain) loss, tax expense (benefit)	(82)	6	(430)	17
Change in net actuarial (gain) loss, net of tax amount	(94)	9	(660)	26
Other comprehensive income, before tax	(1,824)	(2,638)	15,112	13,876
Total other comprehensive income, tax expense (benefit)	(851)	(1,038)	5,961	5,460
Total other comprehensive income, net of tax amount	$ (973)	$ (1,600)	$ 9,151	$ 8,416

Other Comprehensive Income_Lo67

Other Comprehensive Income/Loss - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Net accumulated other comprehensive income:
Net unrealized gain (loss) on investment securities available-for-sale	$ (353)	$ (10,143)
Net unrealized gain (loss) on derivatives	0	(23)
Net actuarial gain (loss) on defined benefit post-retirement benefit plans	1,376	2,038
Net accumulated other comprehensive gain (loss)	$ 1,023	$ (8,128)

Fair Value Measurements - Sche

Fair Value Measurements - Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring and Non-Recurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Related allowance	$ 13,903		$ 13,903		$ 13,954
Write-downs	238	$ 0	294	$ 603
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0		0		0
Deferred compensation plan assets	0		0		0
Deferred compensation plan liabilities	0		0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Non-recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0		0		0
Other real estate owned	0		0		0
Long-lived assets to be disposed of by sale	0		0		0
Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	49,729		49,729		61,794
Deferred compensation plan assets	11,632		11,632		10,627
Deferred compensation plan liabilities	11,632		11,632		10,627
Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Non-recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0		0		0
Other real estate owned	0		0		0
Long-lived assets to be disposed of by sale	0		0		0
Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0		0		0
Deferred compensation plan assets	0		0		0
Deferred compensation plan liabilities	0		0		0
Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Non-recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	34,489		34,489		39,344
Other real estate owned	1,578		1,578		2,110
Long-lived assets to be disposed of by sale	356		356		1,335
Related allowance	13,903		13,903		13,954
Partial loan charge-offs	10,131		10,131		11,941
Write-downs			290	603
Impairment of real estate, received updated appraisal			259	550
Change in management estimates on impairment of real estate			31	$ 53
U.S. Treasury notes | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
U.S. Treasury notes | Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	3,205		3,205		3,612
U.S. Treasury notes | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
Obligations of U.S. government agencies | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
Obligations of U.S. government agencies | Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	505,578		505,578		391,297
Obligations of U.S. government agencies | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
U.S. agency residential mortgage-backed securities & collateralized mortgage obligations | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
U.S. agency residential mortgage-backed securities & collateralized mortgage obligations | Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	1,435,238		1,435,238		1,213,701
U.S. agency residential mortgage-backed securities & collateralized mortgage obligations | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
Private mortgage-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
Private mortgage-backed securities | Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	97,838		97,838		116
Private mortgage-backed securities | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
Corporate securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0
Corporate securities | Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	66,878		66,878
Other investments | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
Other investments | Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	2,960		2,960		2,972
Other investments | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
Estimated Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	2,111,697		2,111,697		1,611,698
Loans held for sale	49,729		49,729		61,794
Derivative assets:	10,721		10,721		2,749
Derivative liabilities:	9,099		9,099		1,314
Deferred compensation plan assets	11,632		11,632		10,627
Deferred compensation plan liabilities	11,632		11,632		10,627
Estimated Fair Value | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	49,729		49,729		61,794
Deferred compensation plan assets	11,632		11,632		10,627
Deferred compensation plan liabilities	11,632		11,632		10,627
Estimated Fair Value | Fair Value Measured on a Non-recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	34,489		34,489		39,344
Other real estate owned	1,578		1,578		2,110
Long-lived assets to be disposed of by sale	356		356		1,335
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
Loans held for sale	0		0		0
Derivative assets:	0		0		0
Derivative liabilities:	0		0		0
Deferred compensation plan assets	0		0		0
Deferred compensation plan liabilities	0		0		0
Estimated Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	2,111,697		2,111,697		1,611,698
Loans held for sale	49,729		49,729		61,794
Derivative assets:	10,721		10,721		2,749
Derivative liabilities:	9,099		9,099		1,314
Deferred compensation plan assets	11,632		11,632		10,627
Deferred compensation plan liabilities	11,632		11,632		10,627
Estimated Fair Value | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	0		0		0
Loans held for sale	0		0		0
Derivative assets:	0		0		0
Derivative liabilities:	0		0		0
Deferred compensation plan assets	0		0		0
Deferred compensation plan liabilities	0		0		0
Impaired loans	34,489		34,489
Estimated Fair Value | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Non-recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	34,489		34,489		39,344
Estimated Fair Value | U.S. Treasury notes | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	3,205		3,205		3,612
Estimated Fair Value | Obligations of U.S. government agencies | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	505,578		505,578		391,297
Estimated Fair Value | U.S. agency residential mortgage-backed securities & collateralized mortgage obligations | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	1,435,238		1,435,238		1,213,701
Estimated Fair Value | Private mortgage-backed securities | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	97,838		97,838		116
Estimated Fair Value | Corporate securities | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	66,878		66,878
Estimated Fair Value | Other investments | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	2,960		2,960		2,972
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available-for-sale:	2,111,697		2,111,697		1,611,698
Loans held for sale	49,729		49,729		61,794
Derivative assets:	10,721		10,721		2,749
Derivative liabilities:	9,099		9,099		1,314
Deferred compensation plan assets	11,632		11,632		10,627
Deferred compensation plan liabilities	11,632		11,632		10,627
Carrying Amount | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Non-recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	58,523		58,523		65,238
Long-lived assets to be disposed of by sale	565		565		2,363
Change During Period | Fair Value Measured on a Non-recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets to be disposed of by sale	209		209		1,028
Interest Rate Swap | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0		0		0
Derivative liabilities:	0		0		0
Interest Rate Swap | Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	8,764		8,764		1,332
Derivative liabilities:	9,099		9,099		1,314
Interest Rate Swap | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0		0		0
Derivative liabilities:	0		0		0
Interest Rate Swap | Estimated Fair Value | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	8,764		8,764		1,332
Derivative liabilities:	9,099		9,099		1,314
Interest Rate Lock Commitments | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0		0		0
Interest Rate Lock Commitments | Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	1,627		1,627		1,131
Interest Rate Lock Commitments | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0		0		0
Interest Rate Lock Commitments | Estimated Fair Value | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	1,627		1,627		1,131
Forward Contracts | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0		0		0
Forward Contracts | Significant Other Observable Inputs (Level 2) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	330		330		286
Forward Contracts | Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0		0		0
Forward Contracts | Estimated Fair Value | Fair Value Measured on a Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	$ 330		$ 330		$ 286

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Inputs, Quantitative Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Impaired Loans | Minimum | Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate of long-lived assets to be disposed of by sale	0.00%
Impaired Loans | Maximum | Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate of long-lived assets to be disposed of by sale	66.00%
Impaired Loans | Weighted Average | Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate of long-lived assets to be disposed of by sale	31.00%
Other Real Estate Owned | Minimum | Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate of long-lived assets to be disposed of by sale	8.00%
Other Real Estate Owned | Maximum | Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate of long-lived assets to be disposed of by sale	96.00%
Other Real Estate Owned | Weighted Average | Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate of long-lived assets to be disposed of by sale	18.00%
Asses to be Disposed of by Sale | Minimum | Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate of long-lived assets to be disposed of by sale	0.00%
Asses to be Disposed of by Sale | Maximum | Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate of long-lived assets to be disposed of by sale	9.00%
Asses to be Disposed of by Sale | Weighted Average | Market Approach Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate of long-lived assets to be disposed of by sale	6.00%
Carrying Amount
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Net loans held for investment	$ 7,427,815	$ 5,340,536
Change During Period | Fair Value Measured on a Non-recurring Basis
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value of long-lived assets to be disposed of by sale	209	1,028
Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Net loans held for investment	7,163,825	5,248,127
Estimated Fair Value | Fair Value Measured on a Non-recurring Basis
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans	34,489	39,344
Other real estate owned	1,578	2,110
Fair Value of long-lived assets to be disposed of by sale	356	1,335
Significant Unobservable Inputs (Level 3) | Fair Value Measured on a Non-recurring Basis
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans	34,489	39,344
Other real estate owned	1,578	2,110
Fair Value of long-lived assets to be disposed of by sale	356	1,335
Significant Unobservable Inputs (Level 3) | Carrying Amount | Fair Value Measured on a Non-recurring Basis
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans	58,523	65,238
Fair Value of long-lived assets to be disposed of by sale	565	2,363
Significant Unobservable Inputs (Level 3) | Estimated Fair Value
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Net loans held for investment		39,344
Impaired loans	34,489
Significant Unobservable Inputs (Level 3) | Estimated Fair Value | Fair Value Measured on a Non-recurring Basis
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans	$ 34,489	$ 39,344

Fair Value Measurements - Sc70

Fair Value Measurements - Schedule of Estimated Fair Values of Financial Instruments by Level of Valuation Inputs (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financial assets:
Investment securities held-to-maturity	$ 510,405	$ 513,273
Carrying Amount
Financial assets:
Cash and cash equivalents	882,834	782,023
Investment securities available-for-sale:	2,111,697	1,611,698
Investment securities held-to-maturity	505,985	512,770
Accrued interest receivable	40,621	29,852
Mortgage servicing rights, net	24,372	18,457
Loans held for sale	49,729	61,794
Net loans held for investment	7,427,815	5,340,536
Derivative assets	10,721	2,749
Deferred compensation plan assets	11,632	10,627
Total financial assets	11,065,406	8,370,506
Financial liabilities:
Total deposits, excluding time deposits	8,751,295	6,324,512
Time deposits	1,182,173	1,051,598
Securities sold under repurchase agreements	635,288	537,556
Other borrowed funds	30,008	6
Accrued interest payable	5,648	5,421
Long-term debt	8,039	27,970
Subordinated debentures held by subsidiary trusts	82,477	82,477
Derivative liabilities	9,099	1,314
Deferred compensation plan liabilities	11,632	10,627
Total financial liabilities	10,715,659	8,041,481
Estimated Fair Value
Financial assets:
Cash and cash equivalents	882,834	782,023
Investment securities available-for-sale:	2,111,697	1,611,698
Investment securities held-to-maturity	510,405	513,273
Accrued interest receivable	40,621	29,852
Mortgage servicing rights, net	38,142	35,656
Loans held for sale	49,729	61,794
Net loans held for investment	7,163,825	5,248,127
Derivative assets	10,721	2,749
Deferred compensation plan assets	11,632	10,627
Total financial assets	10,819,606	8,295,799
Financial liabilities:
Total deposits, excluding time deposits	8,751,295	6,324,512
Time deposits	1,172,783	1,044,670
Securities sold under repurchase agreements	635,288	537,556
Other borrowed funds	30,008	6
Accrued interest payable	5,648	5,421
Long-term debt	8,266	27,477
Subordinated debentures held by subsidiary trusts	92,303	73,554
Derivative liabilities	9,099	1,314
Deferred compensation plan liabilities	11,632	10,627
Total financial liabilities	10,716,322	8,025,137
Quoted Prices in Active Markets for Identical Assets (Level 1) | Estimated Fair Value
Financial assets:
Cash and cash equivalents	882,834	782,023
Investment securities available-for-sale:	0	0
Investment securities held-to-maturity	0	0
Accrued interest receivable	0	0
Mortgage servicing rights, net	0	0
Loans held for sale	0	0
Net loans held for investment	0	0
Derivative assets	0	0
Deferred compensation plan assets	0	0
Total financial assets	882,834	782,023
Financial liabilities:
Total deposits, excluding time deposits	8,751,295	6,324,512
Time deposits	0	0
Securities sold under repurchase agreements	0	0
Other borrowed funds	0	0
Accrued interest payable	0	0
Long-term debt	0	0
Subordinated debentures held by subsidiary trusts	0	0
Derivative liabilities	0	0
Deferred compensation plan liabilities	0	0
Total financial liabilities	8,751,295	6,324,512
Significant Other Observable Inputs (Level 2) | Estimated Fair Value
Financial assets:
Cash and cash equivalents	0	0
Investment securities available-for-sale:	2,111,697	1,611,698
Investment securities held-to-maturity	510,405	513,273
Accrued interest receivable	40,621	29,852
Mortgage servicing rights, net	38,142	35,656
Loans held for sale	49,729	61,794
Net loans held for investment	7,129,336	5,208,783
Derivative assets	10,721	2,749
Deferred compensation plan assets	11,632	10,627
Total financial assets	9,902,283	7,474,432
Financial liabilities:
Total deposits, excluding time deposits	0	0
Time deposits	1,172,783	1,044,670
Securities sold under repurchase agreements	635,288	537,556
Other borrowed funds	30,008	6
Accrued interest payable	5,648	5,421
Long-term debt	8,266	27,477
Subordinated debentures held by subsidiary trusts	92,303	73,554
Derivative liabilities	9,099	1,314
Deferred compensation plan liabilities	11,632	10,627
Total financial liabilities	1,965,027	1,700,625
Significant Unobservable Inputs (Level 3) | Estimated Fair Value
Financial assets:
Cash and cash equivalents	0	0
Investment securities available-for-sale:	0	0
Investment securities held-to-maturity	0	0
Accrued interest receivable	0	0
Mortgage servicing rights, net	0	0
Loans held for sale	0	0
Net loans held for investment		39,344
Impaired loans	34,489
Derivative assets	0	0
Deferred compensation plan assets	0	0
Total financial assets	34,489	39,344
Financial liabilities:
Total deposits, excluding time deposits	0	0
Time deposits	0	0
Securities sold under repurchase agreements	0	0
Other borrowed funds	0	0
Accrued interest payable	0	0
Long-term debt	0	0
Subordinated debentures held by subsidiary trusts	0	0
Derivative liabilities	0	0
Deferred compensation plan liabilities	0	0
Total financial liabilities	$ 0	$ 0

Recent Authoritative Accounti71

Recent Authoritative Accounting Guidance (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Reduction in income tax expense	$ 2.4
Excess tax benefits related to outstanding stock option awards	1.9
Excess tax benefits related to vesting of restricted stock	$ 0.5

Subsequent Events (Details)

Subsequent Events (Details) - Class A Common Stock - $ / shares	9 Months Ended
	Sep. 30, 2017	Oct. 16, 2017
Subsequent Event [Line Items]
Declaration date of quarterly dividend	Oct. 16, 2017
Dividend payment date	Nov. 13, 2017
Dividend record date	Oct. 31, 2017
Subsequent Event
Subsequent Event [Line Items]
Dividend amount per share (in dollars)		$ 0.24