Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities:
Net income	$ 24,583	$ 10,570
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	453	137
Provision for loan losses	2,998	649
Gain on sale of securities		(127)
Gain on sale of loans	(21,166)	(2,643)
Proceeds from sales of loans	10,866,020	3,729,430
Loans and participations originated and purchased for sale	(11,551,090)	(3,776,827)
Change in mortgage servicing rights for paydowns and fair value adjustments	8,338	2,615
Net change in:
Trading securities	(195,266)	33,505
Other assets and receivables	(17,686)	2,699
Other liabilities	9,822	1,933
Other	1,379	798
Net cash provided by (used in) operating activities	(871,615)	2,739
Investing activities:
Net change in securities purchased under agreements to resell	38	37
Purchases of available-for-sale securities	(156,666)	(45,000)
Proceeds from the sale of available-for-sale securities	0	31,086
Proceeds from calls, maturities and paydowns of available-for-sale securities	107,995	49,055
Purchases of loans	(32,631)	(14,233)
Net change in loans receivable	(459,617)	(109,620)
Purchase of Federal Home Loan Bank stock	(25,787)	(11,860)
Proceeds from sale of Federal Home Loan Bank stock		1,190
Purchases of premises and equipment	(594)	(4,206)
Purchase of limited partnership interests	(1,090)
Net cash used in investing activities	(568,352)	(103,551)
Financing activities:
Net change in deposits	1,244,630	(110,031)
Proceeds from Federal Home Loan Bank borrowings	5,597,675	2,348,720
Repayment of Federal Home Loan Bank borrowings	(5,334,998)	(2,209,281)
Proceeds from issuance of preferred stock		48,269
Proceeds from notes payable	450	4,404
Payments on notes payable		(1,500)
Payments of contingent consideration	(501)
Dividends	(5,916)	(2,842)
Net cash provided by financing activities	1,501,340	77,739
Net Change in Cash and Cash Equivalents	61,373	(23,073)
Cash and Cash Equivalents, Beginning of Period	506,709	336,524
Cash and Cash Equivalents, End of Period	568,082	313,451
Additional Cash Flows Information:
Interest paid	23,782	14,745
Income taxes paid	$ 46	$ 64