Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Operating Activities:
Net income	$ 37,889	$ 34,692	$ 75,982	$ 57,241
Adjustment to reconcile net income to net cash provided by operating activities:
Provision for credit losses	1,000	2,000	2,000	3,000
Depreciation and amortization			13,008	12,606
Amortization of intangibles	1,010	869	2,040	1,749
Amortization of debt securities premium and discount, net			3,611	5,200
Share-based compensation expense			4,452	4,679
Security gains, net	(23)	(86)	(1,094)	(88)
Net deferred loan origination expense			(3,429)	(3,335)
Increase in interest receivable			1,289	1,256
Increase (decrease) in interest payable			284	656
Realized gain on mortgages sold			(23,169)	(23,516)
Proceeds from mortgages sold			677,789	745,752
Origination of mortgages held for sale			(673,686)	(777,951)
Loss on other real estate owned, net			960	1,729
Increase in bank-owned life insurance			(3,379)	(3,706)
Other, net			1,226	16,261
Net cash provided by (used in) operating activities			77,884	41,533
Investing activities:
Proceeds from calls and maturities of available-for-sale securities			260,047	224,051
Proceeds from sales of available-for-sale securities			1,071	15
Purchases of available-for-sale securities			(154,360)	(229,469)
Net increase in loans and leases			(211,450)	(210,262)
Purchases of premises and equipment			(15,708)	(11,772)
Proceeds from sale of premises and equipment			185	949
Proceeds from death benefits from COLI			1,799
Acquisition of Insurance Agency				(3,716)
Proceeds from sale of other real estate owned			3,298	6,219
Other, net			(216)	(50)
Net cash provided by (used in) investing activities			(115,334)	(224,035)
Financing activities:
Net increase in deposits			250,155	33,206
Net decrease in short-term debt and other liabilities			(81,187)	(51,997)
Advances of long-term debt				300,000
Repayment of long-term debt				(4,187)
Redemption of Junior Subordinated Debt			(12,888)
Issuance of common stock			864	207
Repurchase of common stock			(91,354)	(971)
Payment of cash dividends			(23,049)	(18,872)
Net cash provided by financing activities			42,541	257,386
Increase in cash and cash equivalents			5,091	74,884
Cash and cash equivalents at beginning of period			222,965	197,969	$ 197,969
Cash and cash equivalents at end of period	$ 228,056	$ 272,853	228,056	272,853	$ 222,965
Supplemental Cash Flow Information
Income tax (refunds) payments, net			44,967	23,304
Interest paid			17,409	13,264
Transfers of loans to other real estate owned			4,155	7,874
MSR fair value adjustment			(707)	(12,046)
Financed sales of other real estate owned			1,442	541
Transfers of loans held for sale to loan portfolio			$ 642	$ 75