Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities
Net Income	$ 108,032	$ 86,830	$ 62,121
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	14,875	6,500	6,100
Gains on sales of loans	(15,686)	(6,354)	(4,451)
Proceeds from sales of loans	723,521	228,995	153,743
Loans originated for sale	(534,422)	(220,765)	(150,795)
Net gains on sale of investment securities	(129)	(630)	0
Net gains from sales/writedowns of other real estate and repossessed assets	(5,212)	(2,681)	(1,886)
Depreciation	13,270	11,028	8,980
Amortization of intangible assets	10,046	8,444	3,345
Additions to loan servicing rights	(4,333)	(1,476)	(1,075)
Valuation change in loan servicing rights	(4,585)	(200)	200
Net amortization of premiums and discounts on investment securities	9,713	6,007	4,497
Share-based compensation expense	13,452	3,478	2,931
Deferred income tax expense (benefit)	24,091	5,700	(1,700)
Net (increase) decrease in interest receivable and other assets	(25,606)	(19,027)	2,322
Net increase (decrease) in interest payable and other liabilities	(46,449)	(2,800)	5,893
Net cash from operating activities	280,578	103,049	90,225
Investment securities — available-for-sale:
Proceeds from maturities, calls and principal reductions	248,772	212,051	165,749
Proceeds from sales and redemptions	41,446	40,301	0
Purchases	(187,702)	0	0
Investment securities — held-to-maturity:
Proceeds from maturities, calls and principal reductions	90,933	87,189	83,989
Purchases	(206,023)	(279,226)	(127,187)
Net increase in loans	(860,135)	(493,776)	(586,121)
Proceeds from sales of other real estate and repossessed assets	22,147	16,653	12,192
Purchases of premises and equipment, net of disposals	(18,098)	(8,527)	(13,411)
Net cash acquired (paid) in business combinations	325,714	16,551	(14,260)
Net cash used in investing activities	(542,946)	(408,784)	(479,049)
Cash flows from financing activities
Net increase in interest- and noninterest-bearing demand deposits and savings accounts	672,584	479,386	277,781
Net decrease in time deposits	(550,847)	(170,598)	(115,642)
Net increase (decrease) in securities sold under agreements to repurchase with customers and other short-term borrowings	401,144	(31,268)	62,039
Proceeds from issuance of long-term borrowings	375,000	125,000	0
Repayment of long-term borrowings	(351,018)	(6,000)	(10,310)
Cash dividends paid	(49,389)	(36,918)	(29,528)
Proceeds from issuance of common stock, net of issuance costs	0	0	76,175
Proceeds from directors' stock plans and exercise of stock options, net of shares withheld	1,572	2,473	1,242
Cash paid for payroll taxes upon conversion of share-based awards	(1,065)	(571)	(701)
Net cash from financing activities	497,981	361,504	261,056
Net increase (decrease) in cash and cash equivalents	235,613	55,769	(127,768)
Cash and cash equivalents at beginning of year	238,789	183,020	310,788
Cash and cash equivalents at end of year	474,402	238,789	183,020
Supplemental disclosures of cash flow information:
Interest paid	25,460	16,958	14,823
Income taxes paid, net of refunds	22,200	41,450	25,900
Loans transferred to other real estate and repossessed assets	12,970	9,329	11,308
Closed branch offices transferred to other assets	4,846	2,692	841
Business combinations:
Fair value of tangible assets acquired (noncash)	6,371,781	1,282,420	747,181
Goodwill, loan servicing rights and other identifiable intangible assets acquired	908,217	118,744	82,090
Liabilities assumed	6,100,901	1,258,051	815,011
Common stock and stock options issued	$ 1,504,811	$ 159,904	$ 0