Condensed Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows from Operating Activities
Net income	$ 118,043,000	$ 100,755,000	$ 12,175,000
(Reversal)/Provision for credit losses	(9,000,000)	27,000,000	156,900,000
Provision for losses on other real estate owned	10,668,000	10,385,000	20,139,000
Deferred tax liability/(benefit)	4,784,000	13,808,000	(38,504,000)
Depreciation	5,939,000	6,079,000	4,619,000
Net gains on sale and transfers of other real estate owned	(369,000)	(5,243,000)	(9,977,000)
Net gains on sale of loans	(633,000)	(3,354,000)	(149,000)
Net gains on sale of loans held for sale		(88,000)	(779,000)
Proceeds from sale of loans	59,589,000	46,377,000	7,481,000
Originations of loans held for sale	(58,930,000)	(14,027,000)	(7,332,000)
Write-downs on loans held for sale			3,160,000
(Decrease)/increase in unrealized loss from interest rate swaps	(2,634,000)	(3,874,000)	5,814,000
Purchase of trading securities	(163,000)	(745,000)	(3,795,000)
Write-down on venture capital and other investments	309,000	379,000	515,000
Write-down on impaired securities	181,000	200,000	492,000
Gain on sales and calls of securities	(18,025,000)	(21,131,000)	(19,253,000)
Other non-cash interest	(200,000)	(480,000)	(794,000)
Amortization of security premiums, net	5,306,000	4,233,000	6,667,000
Amortization of other intangible assets	5,798,000	5,965,000	6,034,000
Excess tax short-fall from stock options	620,000	290,000	539,000
Stock based compensation expense	2,062,000	1,758,000	3,337,000
Stock issued to officers as compensation	788,000
Decrease in accrued interest receivable	6,211,000	3,156,000	600,000
Noncontrolling interest	(605,000)	(605,000)	(610,000)
Decrease/(increase) in other assets, net	37,093,000	(534,000)	34,594,000
(Decrease)/increase in other liabilities	(2,256,000)	3,746,000	(13,368,000)
Net cash provided by operating activities	164,576,000	174,050,000	168,505,000
Cash Flows from Investing Activities
(Increase)/decrease in short-term investments	(117,027,000)	(88,634,000)	48,404,000
Decrease/(increase) in securities purchased under agreements to resell		110,000,000	(110,000,000)
Purchase of investment securities available-for-sale	(517,513,000)	(571,093,000)	(3,366,780,000)
Proceeds from maturity and call of investment securities available-for-sale	552,099,000	435,000,000	2,876,414,000
Proceeds from sale of investment securities available-for-sale	60,951,000	524,958,000	65,139,000
Purchase of mortgage-backed securities available-for-sale	(680,388,000)	(541,356,000)
Proceeds from repayment and sale of mortgage-backed securities available-for-sale	619,169,000	868,023,000	1,351,018,000
Purchase of investment securities held-to-maturity			(150,164,000)
Purchase of mortgage-backed securities held-to-maturity		(480,083,000)	(165,527,000)
Proceeds from maturity and call of investment securities held-to-maturity	376,981,000	163,855,000	108,067,000
Redemption of Federal Home Loan Bank stock	11,717,000	10,884,000	7,918,000
Net increase in loans	(395,743,000)	(362,054,000)	(151,054,000)
Purchase of premises and equipment	(3,108,000)	(2,888,000)	(4,979,000)
Proceeds from sales of other real estate owned	47,866,000	61,406,000	91,154,000
Net increase in investment in affordable housing	(1,540,000)	(968,000)	(3,015,000)
Net cash (used in)/provided by investing activities	(46,536,000)	127,050,000	596,595,000
Cash Flows from Financing Activities
Net increase in demand deposits, NOW accounts, money market and saving deposits	625,360,000	180,940,000	224,122,000
Net (decrease)/increase in time deposits	(471,085,000)	56,828,000	(736,549,000)
Net (decrease)/increase in federal funds purchased and securities sold under agreement to repurchase	(150,000,000)	(161,000,000)	4,000,000
Advances from Federal Home Loan Bank	531,200,000	4,734,000,000	528,000,000
Repayment of Federal Home Loan Bank borrowings	(610,000,000)	(5,059,000,000)	(907,362,000)
Cash dividends	(16,049,000)	(16,046,000)	(16,040,000)
Issuance of common stock			124,928,000
Proceeds from other borrowings			1,253,000
Repayment of other borrowings	(880,000)	(7,584,000)
Proceeds from shares issued to Dividend Reinvestment Plan	291,000	287,000	310,000
Proceeds from exercise of stock options	764,000	1,306,000
Excess tax short-fall from share-based payment arrangements	(620,000)	(290,000)	(539,000)
Net cash used in financing activities	(91,019,000)	(270,559,000)	(777,877,000)
Increase/(decrease) in cash and cash equivalents	27,021,000	30,541,000	(12,777,000)
Cash and cash equivalents, beginning of the year	117,888,000	87,347,000	100,124,000
Cash and cash equivalents, end of the year	144,909,000	117,888,000	87,347,000
Cash paid during the year for:
Interest	112,411,000	142,644,000	197,762,000
Income taxes	36,083,000	53,148,000	13,369,000
Non-cash investing and financing activities:
Net change in unrealized holding gain on securities available-for-sale, net of tax	9,197,000	(7,710,000)	(147,000)
Transfers to other real estate owned from loans held for investment	14,389,000	83,941,000	98,653,000
Transfers to other real estate owned from loans held for sale		2,874,000	21,473,000
Loans transferred to loans held for sale	15,986,000	4,399,000	4,332,000
Loans transferred to loans held for investment from held for sale	500,000
Loans to facilitate the sale of other real estate owned	1,785,000	7,472,000	12,204,000
Loans to facilitate the sale of loans		$ 6,094,000	$ 23,500,000