Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities:
Net income	$ 127,491	$ 116,750	$ 94,115
Adjustment to reconcile net income to net cash provided by operating activities:
Provision for credit losses	(13,000)		7,500
Depreciation and amortization	26,288	27,272	26,544
Deferred taxes	(11,356)	(7,563)	3,358
Amortization of intangibles	3,963	4,443	2,979
Amortization of debt securities premium and discount, net	12,565	13,089	15,062
Share-based compensation expense	5,585	1,201	1,644
Security gains, net	(136)	(37)	(46)
Net deferred loan origination expense	(6,677)	(6,809)	(7,639)
Excess tax benefit from exercise of stock options	(1,079)	(1,856)	(139)
Decrease in interest receivable	1,084	165	2,206
Decrease in interest payable	(329)	(1,436)	(1,304)
Realized gain on mortgages sold	(46,058)	(31,941)	(49,304)
Proceeds from mortgages sold	1,468,729	914,084	1,530,589
Origination of mortgages held for sale	(1,440,411)	(920,689)	(1,424,983)
Loss on other real estate owned, net	5,703	14,545	7,385
Increase in bank-owned life insurance	(7,457)	(8,848)	(8,314)
(Increase) decrease in prepaid pension asset		26,263	(3,705)
Other, net	8,401	3,496	7,784
Net cash provided by operating activities	133,306	142,129	203,732
Investing Activities:
Proceeds from calls and maturities of available-for-sale securities	415,795	584,260	584,926
Proceeds from sales of available-for-sale securities	1,110
Purchases of available-for-sale securities	(374,181)	(252,467)	(718,432)
Net (increase) decrease in loans and leases	(663,573)	(803,858)	(361,383)
Purchases of premises and equipment	(30,401)	(17,211)	(25,459)
Proceeds from sale of premises and equipment	549	527	3,084
Acquisition of businesses, net of cash acquired		(7,060)	(17,360)
Proceeds from sale of other real estate owned	20,723	35,264	54,475
Proceeds of bank-owned life insurance, net of proceeds from death benefits	2,999	1,206
Other, net	(25)	(20)	117
Net cash (used in) provided by investing activities	(627,004)	(459,359)	(480,032)
Financing Activities:
Net (decrease) increase in deposits	358,822	198,503	(314,310)
Net increase (decrease) in short-term debt and other liabilities	76,254	(32,877)	6,403
Redemption of junior subordinated debt securities		(8,248)	(128,866)
Advances of long-term debt		8,000	50,000
Repayment of long-term debt	(8,373)	(8,066)	(1,786)
Issuance of common stock	10,441	11,583	912
Repurchase of common stock	(70,438)	(711)
Excess tax (benefit) expense from exercise of stock options	1,079	1,856	139
Payment of cash dividends	(33,368)	(23,983)	(11,383)
Net cash (used in) provided by financing activities	334,417	146,057	(398,891)
(Decrease) increase in Cash and Cash Equivalents	(159,281)	(171,173)	(675,191)
Cash and Cash Equivalents at Beginning of Year	357,250	528,423	1,203,614
Cash and Cash Equivalents at End of Year	$ 197,969	$ 357,250	$ 528,423