Consolidated Statements of Cash Flows - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 48,190	$ 48,837	$ 38,450
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	3,281	2,428	2,022
Provision for loan losses	10,130	3,605	458
Deferred income taxes	(21,105)	(7,263)	5,763
Net amortization of debt securities	2,415	3,225	3,256
Amortization of intangible assets	2,609	924	1,089
Gain on sale of investment securities	(22)	(86)	(23)
Mortgage loans originated for sale	(138,949)	(157,129)	(135,721)
Proceeds from mortgage loans sold	145,836	154,993	133,552
Gain on sale of other real estate	(93)	(1,837)	(142)
Gain on state tax credits, net	(2,581)	(2,647)	(2,720)
Excess tax benefit of share-based compensation	0	(1,327)	(449)
Share-based compensation	3,427	3,367	3,601
Net accretion of loan discount and indemnification asset	(5,609)	(11,057)	(7,805)
Changes in:
Accrued interest receivable	(158)	(2,718)	(443)
Accrued interest payable	(27)	476	(214)
Other assets	506	(7,739)	10,457
Other liabilities	(44,269)	41,943	7,582
Net cash provided by operating activities	45,791	82,521	47,187
Cash flows from investing activities:
Net cash paid for acquisitions and dispositions	4,456	0	0
Net increase in loans	(270,090)	(328,023)	(290,326)
Net cash proceeds received from FDIC loss share receivable	0	0	2,275
Proceeds from the termination of FDIC loss share agreements	0	0	1,253
Proceeds from the sale of debt securities, available for sale	144,076	2,493	41,069
Proceeds from the paydown or maturity of debt securities, available for sale	143,949	63,502	53,733
Proceeds from the paydown or maturity of debt securities, held to maturity	6,510	3,655	2,284
Proceeds from the redemption of other investments	43,207	52,279	39,929
Proceeds from the sale of state tax credits held for sale	15,314	18,757	16,337
Proceeds from the sale of other real estate	2,779	11,346	7,378
Payments for the purchase of:
Available for sale debt securities	(325,393)	(81,195)	(152,044)
Held to maturity debt securities	0	(40,529)	0
Other investments	(56,412)	(49,645)	(36,046)
State tax credits held for sale	(18,294)	(8,201)	(20,981)
Fixed assets	(2,546)	(2,496)	(2,111)
Net cash used in investing activities	(312,444)	(358,057)	(337,250)
Cash flows from financing activities:
Net increase in noninterest-bearing deposit accounts	96,681	149,296	74,530
Net increase in interest-bearing deposit accounts	61,204	299,474	218,551
Proceeds from the issuance of subordinated notes	0	48,733	0
Proceeds from Federal Home Loan Bank advances	1,716,500	1,357,000	945,900
Repayments of Federal Home Loan Bank advances	(1,544,000)	(1,467,000)	(979,900)
Proceeds from Notes Payable	10,000	0	0
Repayments of Notes Payable	10,000	0	5,700
Debt issuance costs	(1,136)	(1,267)
Net increase (decrease) in other borrowings	(79,417)	6,654	36,143
Cash dividends paid on common stock	(10,249)	(8,211)	(5,259)
Excess tax benefit of share-based compensation	0	1,327	449
Payments for Repurchase of Common Stock	16,636	4,889	0
Payments for Repurchase of Equity	(2,909)	(2,203)	(1,190)
Net cash provided by financing activities	221,174	380,181	283,524
Net increase (decrease) in cash and cash equivalents	(45,479)	104,645	(6,539)
Cash and cash equivalents, beginning of period	198,802	94,157	100,696
Cash and cash equivalents, end of period	153,323	198,802	94,157
Supplemental disclosures of cash flow information:
Cash paid during the period for interest	24,610	13,253	12,583
Cash paid during the period for income taxes	12,449	26,039	15,763
Noncash transactions:
Real Estate Owned, Transfer to Real Estate Owned	564	2,743	8,248
Sales of other real estate financed	$ 0	$ 140	$ 0
Stock Issued During Period, Shares, Acquisitions	141,729	0	0