Fair Value Measurement (Schedule of Carrying Value and Fair Value of Financial Instruments Not Recorded at Fair Value) (Details) (USD $) Share data in Thousands							6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Jun. 30, 2011 Carrying Value [Member]	Dec. 31, 2010 Carrying Value [Member]	Jun. 30, 2011 Estimated Fair Value [Member]	Dec. 31, 2010 Estimated Fair Value [Member]
Cash and cash equivalents	$ 137,033,000		$ 111,946,000				$ 615,882,000	$ 1,004,125,000	$ 615,882,000	$ 1,004,125,000
Trading securities	2,522,000		3,024,000				2,522,000	3,024,000	2,522,000	3,024,000
Securities available for sale	3,177,460,000		2,919,180,000				3,177,460,000	2,919,180,000	3,177,460,000	2,919,180,000
Securities held to maturity	5,553,000		4,762,000				5,553,000	4,762,000	5,733,000	4,774,000
Loans held for sale	60,416,000		75,626,000				60,416,000	75,626,000	60,416,000	75,626,000
Non-covered loans and leases, net	5,735,553,000		5,658,987,000				5,637,758,000	5,557,066,000	5,691,951,000	5,767,506,000
Covered loans and leases, net	698,676,000		785,898,000				698,676,000	785,898,000	783,045,000	893,682,000
Restricted equity securities	32,839,000		34,475,000				32,839,000	34,475,000	32,839,000	34,475,000
Mortgage servicing rights	16,350,000.000	15,605,000.000	14,454,000.000	12,895,000.000	13,628,000.000	12,625,000.000	16,350,000.000	14,454,000.000	16,350,000.000	14,454,000.000
Bank owned life insurance assets							91,169,000	90,161,000	91,169,000	90,161,000
FDIC indemnification asset	116,928,000		146,413,000				116,928,000	146,413,000	63,211,000	90,011,000
Derivatives	1,979,000		1,060,000				1,979,000	1,060,000	1,979,000	1,060,000
Visa Class B common stock							0		18,311	15,987
Deposits	9,146,412,000		9,433,805,000				9,146,412,000	9,433,805,000	9,149,607,000	9,464,406,000
Securities sold under agreements to repurchase	120,889,000		73,759,000				120,889,000	73,759,000	120,889,000	73,759,000
Term debt	256,719,000		262,760,000				256,719,000	262,760,000	278,406,000	282,127,000
Junior subordinated debentures, at fair value	81,766,000		80,688,000				81,766,000	80,688,000	81,766,000	80,688,000
Junior subordinated debentures, at amortized cost	102,705,000		102,866,000				102,705,000	102,866,000	66,799,000	65,771,000
Derivatives	$ 1,518,000		$ 361,000				$ 1,518,000	$ 361,000	$ 1,518,000	$ 361,000