Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest Income:
Interest and fees on loans and leases	$ 129,227	$ 123,257	$ 379,008	$ 365,262
Taxable interest and dividends on securities	46,349	42,722	142,442	128,320
Non-taxable interest on securities	4,099	5,201	13,109	16,586
Loans held for sale	239	573	631	1,761
Total interest income	179,914	171,753	535,190	511,929
Interest Expense:
Deposits	11,345	10,908	32,840	35,782
Securities sold under agreements to repurchase and other borrowings	4,587	5,283	14,874	15,522
Federal Home Loan Bank advances	4,203	3,753	12,052	12,299
Long-term debt	2,409	1,822	7,631	5,482
Total interest expense	22,544	21,766	67,397	69,085
Net interest income	157,370	149,987	467,793	442,844
Provision for loan and lease losses	9,500	8,500	27,750	24,500
Net interest income after provision for loan and lease losses	147,870	141,487	440,043	418,344
Non-interest Income:
Deposit service fees	26,489	25,170	77,503	73,786
Loan related fees	5,479	5,840	14,851	15,930
Wealth and investment services	8,762	8,095	26,429	24,781
Mortgage banking activities	1,805	665	3,093	13,584
Increase in cash surrender value of life insurance policies	3,346	3,516	9,900	10,348
Net gain on sale of investment securities	42	269	4,378	708
Impairment loss recognized in earnings	(85)	0	(246)	0
Other income	5,071	2,702	12,425	7,649
Total non-interest income	50,909	46,257	148,333	146,786
Non-interest Expense:
Compensation and benefits	66,849	64,862	198,931	196,680
Occupancy	11,557	11,994	35,807	36,710
Technology and equipment	15,419	14,895	46,166	45,743
Intangible assets amortization	432	1,242	2,269	3,726
Marketing	4,032	3,649	11,461	12,277
Professional and outside services	2,470	2,254	6,441	5,931
Deposit insurance	5,938	5,300	16,814	15,998
Other expense	17,945	18,085	53,955	54,355
Total non-interest expense	124,642	122,281	371,844	371,420
Income before income tax expense	74,137	65,463	216,532	193,710
Income tax expense	23,679	18,158	67,795	57,915
Net income	50,458	47,305	148,737	135,795
Preferred stock dividends	(2,639)	(2,639)	(7,917)	(8,164)
Net income available to common shareholders	$ 47,819	$ 44,666	$ 140,820	$ 127,631
Net income per common share:
Basic (in dollars per share)	$ 0.53	$ 0.50	$ 1.56	$ 1.44
Diluted (in dollars per share)	$ 0.53	$ 0.49	$ 1.55	$ 1.41