Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest Income
Interest and fees on loans	$ 633,199	$ 552,821	$ 537,301
Interest and dividends on investment securities:
Taxable	52,050	62,458	57,392
Tax-exempt	14,568	14,683	14,426
Dividends	6,557	6,272	6,240
Interest on federal funds sold and other short-term investments	649	369	738
Total interest income	707,023	636,603	616,097
Interest Expense
Savings, NOW and money market	24,824	19,671	17,863
Time	35,432	27,882	29,928
Interest on short-term borrowings	919	972	590
Interest on long-term borrowings and junior subordinated debentures	95,579	113,321	119,996
Total interest expense	156,754	161,846	168,377
Net Interest Income	550,269	474,757	447,720
Provision for credit losses	8,101	1,884	16,095
Net Interest Income After Provision for Credit Losses	542,168	472,873	431,625
Non-Interest Income
Trust and investment services	10,020	9,512	8,610
Insurance commissions	17,233	16,853	15,907
Service charges on deposit accounts	21,176	22,771	24,115
Gains on securities transactions, net	2,487	745	14,678
Fees from loan servicing	6,641	7,013	7,020
Gains on sales of loans, net	4,245	1,731	33,695
Gains on sales of assets, net	2,776	18,087	10,947
Bank owned life insurance	6,815	6,392	5,962
Change in FDIC loss-share receivable	(3,326)	(20,792)	(8,427)
Other	15,735	15,304	16,146
Total non-interest income	83,802	77,616	128,653
Non-Interest Expense
Salary and employee benefits expense	221,765	193,489	194,410
Net occupancy and equipment expense	90,521	74,492	71,634
FDIC insurance assessment	16,867	14,051	16,767
Amortization of other intangible assets	9,169	9,919	8,258
Professional and legal fees	18,945	16,859	16,491
Loss on extinguishment of debt	51,129	10,132	0
Amortization of tax credit investments	27,312	24,196	14,352
Telecommunication expenses	8,259	6,993	6,843
Other	55,108	53,124	52,583
Total non-interest expense	499,075	403,255	381,338
Income (loss) before income taxes	126,895	147,234	178,940
Income tax expense	23,938	31,062	46,979
Net Income	102,957	116,172	131,961
Dividends on preferred stock	3,813	0	0
Net Income Available to Common Shareholders	$ 99,144	$ 116,172	$ 131,961
Earnings Per Common Share:
Basic (in usd per share)	$ 0.42	$ 0.56	$ 0.66
Diluted (in usd per share)	0.42	0.56	0.66
Cash dividends declared per common share (in usd per share)	$ 0.44	$ 0.44	$ 0.60
Weighted Average Number of Common Shares Outstanding:
Basic (in shares)	234,405,909	205,716,293	199,309,425
Diluted (in shares)	234,437,000	205,716,293	199,309,425