CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Interest income:
Interest and fees on loans	$ 47,118	$ 47,638
Interest and dividends on taxable investments	15,216	14,275
Interest and dividends on nontaxable investments	5,591	5,598
Total interest income	67,925	67,511
Interest expense:
Interest on deposits	3,142	5,509
Interest on borrowings	5,730	7,400
Interest on subordinated debt held by unconsolidated subsidiary trusts	628	693
Total interest expense	9,500	13,602
Net interest income	58,425	53,909
Less: Provision for loan losses	1,393	1,644
Net interest income after provision for loan losses	57,032	52,265
Noninterest income:
Deposit service fees	11,595	10,369
Other banking services	1,038	994
Benefit trust, administration, consulting and actuarial fees	9,770	8,973
Wealth management services	3,698	3,132
Gain on sales of investment securities	47,791	0
Loss on debt extinguishments	47,783	0
Total noninterest income	26,109	23,468
Noninterest expenses:
Salaries and employee benefits	30,483	27,425
Occupancy and equipment	7,065	6,463
Data processing and communications	6,277	5,583
Amortization of intangible assets	1,179	1,086
Legal and professional fees	2,399	2,208
Office supplies and postage	1,495	1,468
Business development and marketing	1,479	1,172
FDIC insurance premiums	1,055	906
Acquisition expenses	0	260
Other	3,120	2,832
Total noninterest expenses	54,552	49,403
Income before income taxes	28,589	26,330
Income taxes	8,348	7,504
Net income	$ 20,241	$ 18,826
Basic earnings per share (in dollars per share)	$ 0.51	$ 0.49
Diluted earnings per share (in dollars per share)	$ 0.50	$ 0.48
Cash dividends declared per share (in dollars per share)	$ 0.27	$ 0.26