Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net income	$ 75,677	$ 67,295
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for loan losses	5,400	5,880
Depreciation, amortization and accretion	3,541	2,804
Deferred income tax expense	1,669	5,663
Funding of mortgage loans held for sale	(1,256,233)	(1,516,650)
Proceeds from sales of mortgage loans held for sale	1,245,301	1,579,476
Gains on sales of mortgage loans held for sale	(15,719)	(26,687)
Gains on sales of securities	(57)	(1,186)
Penalty on prepayment of debt	205	2,539
Losses on sales of premises and equipment	553	105
Stock-based compensation expense	3,771	2,563
Decrease in FDIC loss-share indemnification asset, net of accretion	0	2,442
(Increase) decrease in other assets	(2,059)	5,591
Decrease in other liabilities	(9,652)	(5,097)
Net cash provided by operating activities	52,397	124,738
Investing activities
Purchases of securities available for sale	(191,679)	(82,243)
Proceeds from sales of securities available for sale	43,494	4,028
Proceeds from call/maturities of securities available for sale	132,044	117,232
Purchases of securities held to maturity	0	(10,644)
Proceeds from sales of securities held to maturity	4,876	0
Proceeds from call/maturities of securities held to maturity	15,882	109,305
Net increase in loans	(272,618)	(407,570)
Purchases of premises and equipment	(11,925)	(8,958)
Proceeds from sales of premises and equipment	1,255	2,462
Proceeds from sales of other assets	11,485	11,040
Net cash received in acquisition of businesses	41,685	25,263
Net cash used in investing activities	(225,501)	(240,085)
Financing activities
Net increase in noninterest-bearing deposits	6,464	163,406
Net increase in interest-bearing deposits	112,854	85,005
Net increase (decrease) in short-term borrowings	274,554	(157,685)
Proceeds from long-term borrowings	0	98,434
Repayment of long-term debt	(169,961)	(46,964)
Cash paid for dividends	(25,004)	(22,108)
Net stock-based compensation transactions	173	415
Excess tax benefit from stock-based compensation	0	664
Net cash provided by financing activities	199,080	121,167
Net increase in cash and cash equivalents	25,976	5,820
Cash and cash equivalents at beginning of period	306,224	211,571
Cash and cash equivalents at end of period	332,200	217,391
Supplemental disclosures
Cash paid for interest	26,974	19,658
Cash paid for income taxes	29,491	22,731
Noncash transactions:
Transfers of loans to other real estate owned	5,418	5,147
Financed sales of other real estate owned	257	538
Transfers of loans held for sale to loan portfolio	0	15,455
Common stock issued in acquisition of businesses	$ 213,590	$ 55,290