CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating Activities
Net income	$ 119,469	$ 112,406
Adjustments to reconcile net income to net cash used in operating activities:
Provision for loan losses	8,818	36,273
Depreciation, amortization and accretion, net	(11,300)	(37,616)
Net realized gains on securities	(14)
Deferred income taxes	6,013	4,878
Other, net	8,540	11,661
Net change in securities purchased under agreements to resell	(45,224)	(32,624)
Net change in assets segregated for regulatory purposes	(26,343)	(15,227)
Net change in trading securities	(410,877)	(187,958)
Net change in broker-dealer and clearing organization receivables	(157,908)	149,674
Net change in FDIC indemnification asset	24,637	18,486
Net change in other assets	(35,967)	(50,760)
Net change in broker-dealer and clearing organization payables	223,043	(117,398)
Net change in other liabilities	(100,970)	(1,612)
Net change in securities sold, not yet purchased	19,620	34,589
Proceeds from sale of mortgage servicing rights asset	17,499	7,586
Net gains from sales of loans	(416,336)	(469,721)
Loans originated for sale	(11,251,438)	(11,995,553)
Proceeds from loans sold	11,520,363	12,292,342
Net cash used in operating activities	(508,375)	(240,574)
Investing Activities
Proceeds from maturities and principal reductions of securities held to maturity	42,185	141,485
Proceeds from sales, maturities and principal reductions of securities available for sale	248,578	367,307
Purchases of securities held to maturity	(58,831)	(175,781)
Purchases of securities available for sale	(415,282)	(250,896)
Net change in loans	(206,362)	(465,542)
Purchases of premises and equipment and other assets	(20,093)	(31,119)
Proceeds from sales of premises and equipment and other real estate owned	27,333	58,490
Net cash received from (paid for) Federal Home Loan Bank and Federal Reserve Bank stock	14,540	(6,807)
Net cash used in investing activities	(367,932)	(362,863)
Financing Activities
Net change in deposits	547,163	108,834
Net change in short-term borrowings	59,912	317,649
Proceeds from notes payable	285,806	208,794
Payments on notes payable	(303,472)	(134,052)
Proceeds from issuance of common stock		4,139
Payments to repurchase common stock	(27,388)
Dividends paid on common stock	(17,384)
Net cash distributed (to) from noncontrolling interest	(1,193)	676
Taxes paid on employee stock awards netting activity	(2,431)	(2,406)
Other, net	(501)	(704)
Net cash provided by financing activities	540,512	502,930
Net change in cash and cash equivalents	(335,795)	(100,507)
Cash and cash equivalents, beginning of period	690,764	669,445
Cash and cash equivalents, end of period	354,969	568,938
Supplemental Disclosures of Cash Flow Information
Cash paid for interest	57,504	42,399
Cash paid for income taxes, net of refunds	69,863	53,899
Supplemental Schedule of Non-Cash Activities
Conversion of loans to other real estate owned	8,319	14,894
Additions to mortgage servicing rights	$ 8,429	$ 20,309