Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net income	$ 90,930	$ 68,014	$ 59,582
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	7,530	4,750	6,167
Depreciation, amortization and accretion	207	5,953	8,104
Deferred income tax expense	11,037	13,751	9,291
Funding of mortgage loans held for sale	(1,951,144)	(1,483,937)	(547,402)
Proceeds from sales of mortgage loans held for sale	2,031,036	1,647,648	563,808
Gains on sales of mortgage loans held for sale	(31,654)	(25,292)	(8,594)
Gains on sales of securities	(1,186)	(96)	(375)
Loss on extinguishment of debt	2,539	0	0
Losses (gains) on sales of premises and equipment	115	105	(72)
Stock-based compensation	3,117	4,435	3,909
Decrease in FDIC loss share indemnification asset, net of accretion and amortization	2,891	4,409	14,399
Loss on termination of FDIC loss share agreements	2,053	0	0
Decrease in other assets	13,020	12,705	21,303
(Decrease) increase in other liabilities	(16,694)	180	(5,437)
Net cash provided by operating activities	163,797	252,625	124,683
Investing activities
Purchases of securities available for sale	(140,133)	(72,114)	(124,296)
Proceeds from sales of securities available for sale	4,028	8,444	1,099
Proceeds from call/maturities of securities available for sale	158,359	111,663	80,305
Purchases of securities held to maturity	(15,267)	(144,027)	(155,868)
Proceeds from call/maturities of securities held to maturity	119,405	145,449	136,013
Net increase in loans	(504,640)	(298,676)	(120,787)
Purchases of premises and equipment	(13,560)	(25,165)	(22,179)
Proceeds from sales of premises and equipment	2,462	2,219	2,911
Proceeds from sales of other assets	16,939	0	0
Payment made to FDIC to terminate loss share agreements	(4,849)	0	0
Net cash received in acquisition	25,263	24,776	0
Net cash used in investing activities	(351,993)	(247,431)	(202,802)
Financing activities
Net increase in noninterest-bearing deposits	209,943	79,342	63,852
Net (decrease) increase in interest-bearing deposits	279,146	(77,124)	(67,346)
Net (decrease) increase in short-term borrowings	(314,952)	375,220	30,120
Proceeds from long-term debt	98,385	40	0
Repayment of long-term debt	(47,230)	(308,766)	(13,557)
Cash paid for dividends	(29,734)	(24,557)	(21,518)
Cash received on exercise of stock options	415	102	401
Excess tax benefits from exercise of stock options	2,771	537	1,102
Proceeds from equity offering	84,105	0	0
Net cash provided by (used in) financing activities	282,849	44,794	(6,946)
Net increase (decrease) in cash and cash equivalents	94,653	49,988	(85,065)
Cash and cash equivalents at beginning of year	211,571	161,583	246,648
Cash and cash equivalents at end of year	306,224	211,571	161,583
Supplemental disclosures
Cash paid for interest	25,871	21,615	24,103
Cash paid for income taxes	22,731	18,610	17,503
Noncash transactions:
Transfers of loans to other real estate	8,870	14,935	15,692
Financed sales of other real estate owned	2,070	1,134	860
Transfers of loans held for sale to loan portfolio	17,838	11,096	0
Common stock issued in acquisition of businesses	$ 55,290	$ 281,530	$ 0