CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Cash flows from operating activities:
Net Income	$ 20,664	$ 46,810	$ 209,835	$ 220,796
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Provision for loan losses			253,936	128,651
Goodwill impairment charge	0	3,801	0	3,801
Amortization of intangibles			7,034	9,308
Depreciation and amortization of premises and equipment			35,966	34,725
Net accretion of discounts and amortization of premiums and deferred fees			(17,371)	(36,753)
Impairment losses on long-lived assets			11,286	0
Other-than-temporary impairment on investment securities	0	0	8,299	209
Fair value adjustments on mortgage servicing rights			24,262	18,879
FDIC loss share (income) expense			12,680	77,445
Adjustments (expense) to indemnity reserves on loans sold	6,406	4,390	11,302	14,234
Earnings from investments under the equity method			(27,350)	(23,812)
Deferred income tax (benefit) expense			30,471	61,918
(Gain) loss on:
Disposition of premises and equipment and other productive assets			5,018	3,603
Sale and valuation adjustments of investment securities			(284)	(1,932)
Sale of loans, including valuation adjustments on loans held-for-sale and mortgage banking activities			(16,455)	(32,982)
Sale of foreclosed assets, including write-downs			19,228	13,160
Acquisitions of loans held-for-sale			(204,813)	(223,189)
Proceeds from sale of loans held-for-sale			68,326	58,003
Net originations on loans held-for-sale			(283,709)	(365,353)
Net (increase) decrease in:
Trading securities			498,840	578,133
Accrued income receivable			(8,297)	4,543
Other assets			13,454	(28,201)
Net increase (decrease) in:
Interest payable			(9,299)	(11,553)
Pension and other postretirement benefits obligation			(13,760)	(56,537)
Other liabilities			15,178	(5,292)
Total adjustments			433,942	221,008
Net cash provided by operating activities			643,777	441,804
Cash flows from investing activities:
Net (increase) decrease in money market investments			(2,597,994)	(1,783,402)
Purchases of investment securities:
Available-for-sale			(2,356,389)	(2,408,514)
Other			(23,822)	(14,017)
Proceeds from calls, paydowns, maturities and redemptions of investment securities:
Available-for-sale			1,225,915	951,447
Held-to-maturity			6,229	4,182
Other			0	11,051
Proceeds from sale of investment securities available-for-sale			14,888	1,556
Proceeds from sale of other investment securities			17,675	8,006
Net repayments on loans			(77,400)	(93,354)
Proceeds from sale of loans			415	134,114
Acquisition of loan portfolios			(448,121)	(355,507)
Acquisition of trademark			0
Net payments from FDIC under loss sharing agreements			(11,520)	95,407
Return of capital from equity method investments			8,556	324
Acquisition of premises and equipment			(40,158)	(78,297)
Proceeds from sale of:
Premises and equipment and other productive assets			6,982	5,519
Foreclosed assets			85,705	54,600
Net cash provided by investing activities			(4,189,039)	(3,466,885)
Net increase (decrease) in:
Deposits			3,751,367	3,119,674
Federal funds purchased and assets sold under agreements to repurchase			(105,020)	3,106
Other short-term borrowings			239,398	0
Payments of notes payable			(89,375)	(230,608)
Proceeds from issuance of notes payable			45,000	165,047
Proceeds from issuance of common stock			5,515	5,718
Dividends paid			(69,162)	(49,438)
Net payments for repurchase of common stock			(75,662)	(1,547)
Payments related to tax witholding for shared-based compensation			(1,756)	0
Net cash used in financing activities			3,700,305	3,011,952
Net decrease in cash and due from banks			155,043	(13,129)
Cash and due from banks at beginning of period			362,394	363,674	$ 363,674
Cash and due from banks at end of period	$ 517,437	$ 350,545	$ 517,437	$ 350,545	$ 362,394