CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Activities
Net income	$ 53,602	$ 39,777
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for credit losses	34,549	951
Depreciation, amortization and accretion, net	1,883	(2,283)
Net realized losses (gains) on securities	(158)
Net change in fair value of equity securities	59	(24)
Deferred income taxes	(2,053)	876
Other, net	(2,311)	2,601
Net change in securities purchased under agreements to resell	35,675	(3,594)
Net change in trading securities	295,995	42,171
Net change in broker-dealer and clearing organization receivables	11,768	(124,407)
Net change in other assets	(243,683)	(534)
Net change in broker-dealer and clearing organization payables	(281,891)	119,673
Net change in other liabilities	(73,963)	(55,210)
Net change in securities sold, not yet purchased	(21,049)	(12,313)
Proceeds from sale of mortgage servicing rights asset	18,650
Net gains from sales of loans	(150,486)	(96,139)
Loans originated for sale	(4,256,981)	(2,596,880)
Proceeds from loans sold	3,994,119	3,009,282
Net Cash Provided by (Used in) Operating Activities, Continuing Operations, Total	(586,275)	323,947
Net cash provided by operating activities for discontinued operations	3,505	2,155
Net cash provided by (used in) operating activities	(582,770)	326,102
Investing Activities
Proceeds from maturities and principal reductions of securities held to maturity	37,624	6,340
Proceeds from sales, maturities and principal reductions of securities available for sale	73,889	30,620
Purchases of securities held to maturity	(6,532)	(25,243)
Purchases of securities available for sale	(119,778)	(172,511)
Net change in loans held for investment	(19,692)	(159,202)
Purchases of premises and equipment and other assets	(17,754)	(8,454)
Proceeds from sales of premises and equipment and other real estate owned	15,350	5,892
Net cash received from (paid for) Federal Home Loan Bank and Federal Reserve Bank stock	18,685	7,172
Net cash used in investing activities for continuing operations	(18,208)	(315,386)
Net cash provided by investing activities for discontinued operations	1,794	8,576
Net cash provided by investing activities	(16,414)	(306,810)
Financing Activities
Net change in deposits	850,829	(162,408)
Net change in short-term borrowings	(94,062)	(151,282)
Proceeds from notes payable	273,386	134,639
Payments on notes payable	(285,639)	(138,160)
Payments to repurchase common stock	(14,957)
Dividends paid on common stock	(8,158)	(7,464)
Net cash received from (distributed to) noncontrolling interest	(2,701)	(1,810)
Taxes paid on employee stock awards netting activity	(469)	(723)
Other, net	(155)	(69)
Net cash provided by financing activities	718,074	(327,277)
Net change in cash, cash equivalents and restricted cash	118,890	(307,985)
Cash, cash equivalents and restricted cash, beginning of period	642,789	778,466
Cash, cash equivalents and restricted cash, end of period	761,679	470,481
Supplemental Disclosures of Cash Flow Information
Cash paid for interest	37,041	39,297
Cash paid for income taxes, net of refunds	1,771	(270)
Supplemental Schedule of Non-Cash Activities
Derecognition of construction in progress related to build-to-suit lease obligations		29,195
Conversion of loans to other real estate owned	182	1,578
Additions to mortgage servicing rights	$ 4,475	$ 1,861