Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest income
Interest and fees on loans	$ 613,024	$ 588,435	$ 583,872
Interest bearing deposits with banks	1,472	1,644	1,552
Federal funds sold and securities purchased under resale agreements	25	27	38
Available-for-sale securities	52,951	37,025	38,134
Trading account securities	79	25	28
Federal Home Loan Bank and Federal Reserve Bank stock	2,920	2,773	2,550
Brokerage customer receivables	796	780	847
Total interest income	671,267	630,709	627,021
Interest expense
Interest on deposits	48,411	53,191	68,305
Interest on Federal Home Loan Bank advances	10,523	11,014	12,103
Interest on other borrowings	1,773	4,341	14,053
Interest on subordinated notes	3,906	167	428
Interest on junior subordinated debentures	8,079	11,369	12,616
Total interest expense	72,692	80,082	107,505
Net interest income	598,575	550,627	519,516
Provision for credit losses	20,537	46,033	76,436
Net interest income after provision for credit losses	578,038	504,594	443,080
Non-interest income
Wealth management	71,343	63,042	52,680
Mortgage banking	91,617	106,857	109,970
Service charges on deposit accounts	23,307	20,366	16,971
(Losses) gains on available-for-sale securities, net	(504)	(3,000)	4,895
Fees from covered call options	7,859	4,773	10,476
Gain on bargain purchases, net	0	0	7,503
Trading (losses) gains, net	(1,609)	892	(1,900)
Other	23,227	29,467	25,497
Total non-interest income	215,240	222,397	226,092
Non-interest expense
Salaries and employee benefits	335,506	308,794	288,589
Equipment	29,751	26,450	23,222
Occupancy, net	42,889	36,633	32,294
Data processing	19,336	18,672	15,739
Advertising and marketing	13,571	11,051	9,438
Professional fees	15,574	14,922	15,262
Amortization of other intangible assets	4,692	4,627	4,324
FDIC insurance	12,168	12,728	13,422
OREO expenses, net	9,367	5,834	22,103
Other	63,993	62,840	64,647
Total non-interest expense	546,847	502,551	489,040
Income before taxes	246,431	224,440	180,132
Income tax expense	95,033	87,230	68,936
Net income	151,398	137,210	111,196
Preferred stock dividends and discount accretion	6,323	8,395	9,093
Net income applicable to common shares	$ 145,075	$ 128,815	$ 102,103
Net income per common share - Basic	$ 3.12	$ 3.33	$ 2.81
Net income per common share - Diluted	$ 2.98	$ 2.75	$ 2.31
Cash dividends declared per common share	$ 0.40	$ 0.18	$ 0.18
Weighted average common shares outstanding	46,524	38,699	36,365
Dilutive potential common shares	4,321	11,249	11,669
Average common shares and dilutive common shares	50,845	49,948	48,034