CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating Activities
Net income	$ 96,169	$ 119,469
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision (recovery) for loan losses	(1,838)	8,818
Depreciation, amortization and accretion, net	3,558	(11,300)
Net realized gains on securities		(14)
Net change in fair value of equity securities	396
Deferred income taxes	653	6,013
Other, net	6,355	8,540
Net change in securities purchased under agreements to resell	21,881	(45,224)
Net change in trading securities	70,371	(410,877)
Net change in broker-dealer and clearing organization receivables	(42,516)	(157,908)
Net change in FDIC indemnification asset		24,637
Net change in other assets	39,208	(35,967)
Net change in broker-dealer and clearing organization payables	85,409	223,043
Net change in other liabilities	(79,283)	(100,970)
Net change in securities sold, not yet purchased	(53,239)	19,620
Proceeds from sale of mortgage servicing rights asset	9,303	17,499
Net gains from sales of loans	(354,488)	(416,336)
Loans originated for sale	(11,148,919)	(11,251,438)
Proceeds from loans sold	11,665,782	11,520,363
Net cash provided by (used in) operating activities	318,802	(482,032)
Investing Activities
Proceeds from maturities and principal reductions of securities held to maturity	36,729	42,185
Proceeds from sales, maturities and principal reductions of securities available for sale	190,266	248,578
Proceeds from sales, maturities and principal reductions of equity securities	3
Purchases of securities held to maturity	(29,377)	(58,831)
Purchases of securities available for sale	(276,710)	(415,282)
Purchases of equity securities	(719)
Net change in loans	(113,918)	(206,362)
Purchases of premises and equipment and other assets	(60,473)	(20,093)
Proceeds from sales of premises and equipment and other real estate owned	18,440	27,333
Net cash received from (paid for) Federal Home Loan Bank and Federal Reserve Bank stock	(5,447)	14,540
Net cash paid for acquisition	(63,245)
Net cash used in investing activities	(304,451)	(367,932)
Financing Activities
Net change in deposits	(40,850)	547,163
Net change in short-term borrowings	10,225	59,912
Proceeds from notes payable	455,776	285,806
Payments on notes payable	(444,312)	(303,472)
Payments to repurchase common stock	(38,821)	(27,388)
Dividends paid on common stock	(20,074)	(17,384)
Net cash contributed from (distributed to) noncontrolling interest	18,367	(1,193)
Taxes paid on employee stock awards netting activity	(1,806)	(2,431)
Other, net	(551)	(501)
Net cash provided by (used in) financing activities	(62,046)	540,512
Net change in cash and cash equivalents	(47,695)	(309,452)
Cash and cash equivalents, beginning of period	673,960	871,757
Cash and cash equivalents, end of period	626,265	562,305
Reconciliation of Cash, Cash Equivalents and Restricted Cash to Consolidated Balance Sheets
Total cash, cash equivalents and restricted cash	673,960	871,757
Supplemental Disclosures of Cash Flow Information
Cash paid for interest	101,402	57,504
Cash paid for income taxes, net of refunds	5,806	69,863
Supplemental Schedule of Non-Cash Activities
Construction in progress related to build-to-suit lease obligations	23,773
Conversion of loans to other real estate owned	5,868	8,319
Additions to mortgage servicing rights	$ 21,090	$ 8,429