Condensed Consolidated Statements Of Cash Flows (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 48,780,000	$ 31,252,000
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of investment premiums, net	21,778,000	16,367,000
Gain on sale of investment securities, net	(1,178,000)	(5,678,000)
Other-than-temporary impairment on investment securities held to maturity		72,000
(Gain) loss on sale of non-covered other real estate owned	(643,000)	1,160,000
Gain on sale of covered other real estate owned	(723,000)	(898,000)
Valuation adjustment on non-covered other real estate owned	4,719,000	5,518,000
Valuation adjustment on covered other real estate owned	3,346,000	1,921,000
Provision for non-covered loan and lease losses	9,805,000	30,489,000
Provision for covered loan and lease losses	1,375,000	11,023,000
Change in FDIC indemnification asset	5,885,000	2,646,000
Depreciation, amortization and accretion	7,949,000	6,218,000
Increase in mortgage servicing rights	(6,281,000)	(2,407,000)
Change in mortgage servicing rights carried at fair value	1,952,000	511,000
Change in junior subordinated debentures carried at fair value	1,007,000	1,078,000
Stock-based compensation	1,942,000	1,987,000
Net (increase) decrease in trading account assets	(992,000)	502,000
Gain on sale of loans	(14,571,000)	(1,819,000)
Origination of loans held for sale	(786,697,000)	(290,058,000)
Proceeds from sales of loans held for sale	690,352,000	307,087,000
Excess tax benefits from the exercise of stock options	(49,000)	(4,000)
Change in other assets and liabilities:
Net decrease in other assets	1,807,000	5,954,000
Net increase in other liabilities	11,199,000	4,759,000
Net cash provided by operating activities	762,000	127,680,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of investment securities available for sale	(419,078,000)	(690,720,000)
Purchases of investment securities held to maturity		(1,573,000)
Proceeds from investment securities available for sale	727,750,000	441,721,000
Proceeds from investment securities held to maturity	363,000	757,000
Redemption of restricted equity securities	869,000	1,636,000
Net non-covered loan and lease originations	(239,262,000)	(136,582,000)
Net covered loan and lease paydowns	56,468,000	63,417,000
Proceeds from sales of loans	5,964,000	6,777,000
Proceeds from disposals of furniture and equipment	1,508,000	180,000
Purchases of premises and equipment	(12,197,000)	(16,877,000)
Net proceeds from FDIC indemnification asset	21,418,000	48,850,000
Proceeds from sales of non-covered other real estate owned	12,208,000	17,026,000
Proceeds from sales of covered other real estate owned	8,733,000	7,355,000
Net cash provided (used) by investing activities	164,744,000	(258,033,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net decrease in deposit liabilities	(104,348,000)	(286,867,000)
Net increase in securities sold under agreements to repurchase	24,736,000	47,130,000
Repayment of term debt		(5,000,000)
Dividends paid on common stock	(15,777,000)	(11,506,000)
Excess tax benefits from stock based compensation	49,000	4,000
Proceeds from stock options exercised	78,000	309,000
Retirement of common stock	(5,234,000)	(1,960,000)
Net cash used by financing activities	(100,496,000)	(257,890,000)
Net increase (decrease) in cash and cash equivalents	65,010,000	(388,243,000)
Cash and cash equivalents, beginning of period	598,766,000	1,004,125,000
Cash and cash equivalents, end of period	663,776,000	615,882,000
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest	27,573,000	41,302,000
Income taxes	13,800,000	6,850,000
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Change in unrealized gains on investment securities available for sale, net of taxes	(3,124,000)	11,983,000
Change in unrealized losses on investment securities held to maturity related to factors other than credit, net of taxes	79,000	26,000
Cash dividend declared on common and preferred stock and payable after period-end	10,139,000	5,754,000
Transfer of non-covered loans to non-covered other real estate owned	8,993,000	25,322,000
Transfer of covered loans to covered other real estate owned	1,346,000	8,668,000
Transfer of covered loans to non-covered loans	9,299,000	4,114,000
Transfer from FDIC indemnification asset to due from FDIC and other	16,399,000	26,839,000
Receivable from sales of covered other real estate owned	$ 290,000