Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash Flows from Operating Activities
Interest and dividends received	$ 95,475	$ 105,673
Service charges and other fees received	8,636	9,644
Interest paid	(1,859)	(4,589)
Net cash paid to vendors, employees and others	(56,221)	(35,201)
Income taxes	907	0
Net cash provided by operating activities	46,938	75,527
Cash Flows from Investing Activities
Net change in interest-earning balances from depository institutions	15,815	(20,868)
Proceeds from repayment of investment securities available-for-sale	224,104	92,519
Proceeds from maturity of investment securities available-for-sale	0	2,390
Purchases of investment securities available-for-sale	(661,857)	0
Proceeds from repayment and maturity of investment securities held-to-maturity	35,766	33,297
Purchases of investment securities held-to-maturity	(545,681)	(1,509)
Net increase in equity investments	(4,961)	(2,985)
Net decrease in loan and lease finance receivables	64,167	103,890
Proceeds from sale of building, net of selling costs	1,157	0
Purchase of premises and equipment	(662)	(882)
Proceeds from BOLI death benefit	5,062	138
Proceeds from sales of other real estate owned	2,216	0
Net cash (used in) provided by investing activities	(864,874)	205,990
Cash Flows from Financing Activities
Net increase in other deposits	336,518	403,546
Net increase in time deposits	5,636	5,130
Net increase (decrease) in customer repurchase agreements	66,940	(59,744)
Cash dividends on common stock	(24,408)	(25,252)
Repurchase of common stock	(502)	(85,018)
Proceeds from exercise of stock options	891	42
Net cash provided by financing activities	385,075	238,704
Net (decrease) increase in cash and cash equivalents	(432,861)	520,221
Cash and cash equivalents, beginning of period	1,958,160	185,518
Cash and cash equivalents, end of period	1,525,299	705,739
Reconciliation of Net Earnings to Net Cash Provided by Operating Activities
Net earnings	63,893	37,980
Adjustments to reconcile net earnings to net cash provided by operating activities:
Gain on sale of building, net	(189)	0
Gain on sale of other real estate owned	(399)	0
Increase in BOLI	(4,624)	(1,344)
Net amortization of premiums and discounts on investment securities	6,411	2,620
Accretion of discount for acquired loans, net	(4,028)	(4,776)
(Recapture of) provision for credit losses	(19,500)	12,000
Stock-based compensation	1,282	1,617
Depreciation and amortization, net	(3,526)	5,176
Change in other assets and liabilities	7,618	22,254
Total adjustments	(16,955)	37,547
Net cash provided by operating activities	46,938	75,527
Supplemental Disclosure of Non-cash Investing Activities
Securities purchased and not settled	$ 80,973	$ 0