CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Cash flows from operating activities:
Net Income	$ 92,945	$ 84,999
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Provision for loan losses	40,698	44,835
Amortization of intangibles	2,345	3,114
Depreciation and amortization of premises and equipment	11,799	11,707
Net accretion of discounts and amortization of premiums and deferred fees	(6,463)	(11,158)
Fair value adjustments on mortgage servicing rights	5,954	8,477
FDIC loss share (income) expense	8,257	3,146
Adjustments (expense) to indemnity reserves on loans sold	1,966	4,098
Earnings from investments under the equity method	(10,879)	(7,089)
Deferred income tax (benefit) expense	25,060	23,218
(Gain) loss on:
Disposition of premises and equipment and other productive assets	6,466	(1,946)
Sale and valuation adjustments of investment securities	(162)	0
Sale of loans, including valuation adjustments on loans held-for-sale and mortgage banking activities	(5,381)	(7,101)
Sale of foreclosed assets, including write-downs	4,512	2,802
Acquisitions of loans held-for-sale	(73,043)	(66,451)
Proceeds from sale of loans held-for-sale	29,364	22,253
Net originations on loans held-for-sale	(123,336)	(110,528)
Net (increase) decrease in:
Trading securities	177,153	176,598
Accrued income receivable	10,024	3,926
Other assets	13,161	20,996
Net increase (decrease) in:
Interest payable	(11,281)	(12,261)
Pension and other postretirement benefits obligation	331	1,536
Other liabilities	(13,654)	(17,010)
Total adjustments	92,891	93,162
Net cash provided by operating activities	185,836	178,161
Cash flows from investing activities:
Net (increase) decrease in money market investments	(763,130)	262,632
Purchases of investment securities:
Available-for-sale	(1,216,880)	(742,859)
Other	(225)	(59,786)
Proceeds from calls, paydowns, maturities and redemptions of investment securities:
Available-for-sale	222,677	239,399
Held-to-maturity	2,184	2,108
Other	0	41,664
Proceeds from sale of investment securities available-for-sale	381	0
Proceeds from sale of other investment securities	1,757	26,346
Net repayments on loans	99,306	13,335
Proceeds from sale of loans	0	1,128
Acquisition of loan portfolios	(109,098)	(212,798)
Net payments from FDIC under loss sharing agreements	(23,574)	88,588
Return of capital from equity method investments	3,862	206
Acquisition of premises and equipment	(18,646)	(38,819)
Proceeds from sale of:
Premises and equipment and other productive assets	3,011	5,092
Foreclosed assets	27,547	14,513
Net cash provided by investing activities	(1,770,828)	(359,251)
Net increase (decrease) in:
Deposits	1,715,958	318,550
Federal funds purchased and assets sold under agreements to repurchase	(44,711)	(1,991)
Other short-term borrowings	0	5,170
Payments of notes payable	(17,408)	(108,452)
Proceeds from issuance of notes payable	0	28,883
Proceeds from issuance of common stock	1,806	2,109
Dividends paid	(16,499)	(16,473)
Net payments for repurchase of common stock	(75,604)	(77)
Payments related to tax witholding for shared-based compensation	(719)	(680)
Net cash used in financing activities	1,562,823	227,039
Net decrease in cash and due from banks	(22,169)	45,949
Cash and due from banks at beginning of period	362,394	363,674	$ 363,674
Cash and due from banks at end of period	$ 340,225	$ 409,623	$ 362,394