Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash Flows from Operating Activities
Net income	$ 102,252	$ 91,693
Adjustments to reconcile net income to net cash provided by/(used in) operating activities:
Credit for loan losses	(8,800)	(3,000)
Provision/(credit) for losses on other real estate owned	1,693	(675)
Deferred tax (asset)/liability	13,846	(12,325)
Depreciation	5,336	4,899
Net gains on sale and transfer of other real estate owned	(3,467)	(843)
Net gains on sale of loans	(300)	(864)
Proceeds from sales of loans	15,791	41,219
Originations of loans held-for-sale	(15,491)	(40,356)
Net change in trading securities		(152)
Income associated with debt redemption	(550)
Write-downs on venture capital investments	317	295
Write-downs on impaired securities	820
Net gains on sales and calls of securities	(7,647)	(27,157)
Amortization/accretion of security premiums/discounts, net	2,266	3,439
Amortization of other intangible assets	575	4,192
Excess tax short-fall from share-based payment arrangements	1,177	143
Stock based compensation and stock issued to officers as compensation	2,948	2,775
Net change in accrued interest receivable and other assets	1,691	24,875
Net change in other liabilities	(8,377)	4,195
Net cash provided by operating activities	104,080	92,353
Cash Flows from Investing Activities
(Increase)/decrease in short-term investments	(75,873)	22,959
Purchase of investment securities available-for-sale	(892,706)	(1,026,659)
Proceeds from sale of investment securities available-for-sale	543,305	903,915
Proceeds from repayments, maturities and calls of investment securities available-for-sale	640,478	367,026
Proceeds from repayments, maturities and calls of investment securities held-to-maturity		50,973
Purchase of Federal Home Loan Bank stock	(17,736)
Redemptions of Federal Home Loan Bank stock	8,646	12,589
Net increase in loans	(763,211)	(413,405)
Purchase of premises and equipment	(4,036)	(4,734)
Proceeds from sale of other real estate owned	28,543	9,926
Net increase in investment in affordable housing	(5,617)	(6,167)
Net cash used in investing activities	(538,207)	(83,577)
Cash Flows from Financing Activities
Net increase in deposits	713,362	534,306
Net decrease in federal funds purchased and securities sold under agreements to repurchase	(250,000)	(450,000)
Advances from Federal Home Loan Bank	8,252,400	1,742,396
Repayment of Federal Home Loan Bank borrowings	(8,218,600)	(1,512,000)
Cash dividends paid	(15,133)	(8,631)
Redemption of series B preferred stock		(258,000)
Repurchase of trust preferred securities	(1,450)
Proceeds from shares issued under Dividend Reinvestment Plan	1,554	202
Taxes paid related to net share settlement of RSUs	(274)
Excess tax short-fall from share-based payment arrangements	(1,177)	(143)
Net cash provided by financing activities	480,682	48,130
Increase in cash and cash equivalents	46,555	56,906
Cash and cash equivalents, beginning of the period	153,747	144,909
Cash and cash equivalents, end of the period	200,302	201,815
Cash paid during the period:
Interest	59,478	65,372
Income taxes paid	52,864	55,537
Non-cash investing and financing activities:
Net change in unrealized holding (loss)/gain on securities available-for-sale, net of tax	21,057	(21,648)
Net change in unrealized holding loss on cash flow hedge derivatives	(163)
Transfers of investment securities to available-for-sale from held-to-maturity		722,466
Transfers of trading securities to short-term investments	4,936
Transfers to other real estate owned from loans held for investment	(2,810)	11,877
Loans to facilitate the sale of other real estate owned		75
Transfer of securities sold but not yet settled to other assets		$ 12,469