Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating Activities:
Net income	$ 208,690	$ 120,823
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	68,104	71,870
Securities impairment	309	242
Amortization of intangibles	1,592	2,525
Accretion of discount, loan fees and purchase market adjustments, net	(16,747)	(29)
Provision for loan losses	57,029	80,139
Net change in trading account assets	4,031	65,829
Net change in trading account liabilities	30,102	(40,247)
Originations and purchases of loans held for sale	(141,761)	(141,690)
Sale of loans held for sale	135,999	176,827
Deferred tax expense	830	28,504
(Gain) loss on sale of premises and equipment	(668)	1,446
Gain on sale of mortgage loans held for sale	(3,529)	(4,621)
Net (gain) loss on sale of other real estate and other assets	(744)	1,072
Increase in other assets	(151,479)	(140,342)
Increase in other liabilities	76,980	5,024
Net cash provided by operating activities	268,738	227,372
Investing Activities:
Proceeds from prepayments, maturities and calls of debt securities available for sale	794,564	561,658
Purchases of debt securities available for sale	(1,136,063)	(726,963)
Proceeds from sales of equity securities	228,497	75,145
Purchases of equity securities	(205,007)	(70,132)
Proceeds from prepayments, maturities and calls of debt securities held to maturity	48,824	46,492
Purchases of debt securities held to maturity	0	(642)
Proceeds from sales of trading securities	0	228,980
Purchases of trading securities	0	(42,463)
Net change in loan portfolio	(648,254)	188,712
Proceeds from sales of loans	8,475	128,842
Purchase of premises and equipment	(23,318)	(22,086)
Proceeds from sale of premises and equipment	1,051	80
Payments to FDIC for covered assets	0	(1,091)
Proceeds from settlement of BOLI policies	2,237	237
Cash payments for premiums of BOLI policies	(9)	(9)
Proceeds from sales of other real estate owned	6,611	5,153
Net cash (used in) provided by investing activities	(922,392)	371,913
Financing Activities:
Net increase in demand deposits, NOW accounts and savings accounts	762,147	1,603,782
Net decrease in time deposits	(78,994)	(1,356,449)
Net (decrease) increase in federal funds purchased and securities sold under agreements to repurchase	(13,658)	32,507
Net increase (decrease) in other short-term borrowings	12,003	(160,438)
Proceeds from FHLB and other borrowings	4,700,000	1,150,000
Repayment of FHLB and other borrowings	(5,300,052)	(1,150,050)
Capital contribution for non-controlling interest	16	46
Preferred dividends paid	(3,864)	(3,548)
Net cash provided by financing activities	77,598	115,850
Net (decrease) increase in cash, cash equivalents and restricted cash	(576,056)	715,135
Cash, cash equivalents and restricted cash at beginning of year	4,270,950	3,419,488
Cash, cash equivalents and restricted cash at end of period	$ 3,694,894	$ 4,134,623