CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net income	$ 65,141	$ 10,567
Adjustments to reconcile net income to net cash provided by operating activities:
(Recovery of) provision for credit losses	(20,160)	56,646
Depreciation of premises and equipment, net	3,090	4,572
Accretion of fees and discounts, net	(16,472)	(13,273)
Amortization of intangible assets	2,651	2,764
Amortization of right of use lease asset	3,100	4,834
Decrease in operating lease liability	(4,113)	(4,466)
Income from mortgage banking activities, net	(8,600)	(3,471)
Gain on sale of securities, net	(329)	(693)
Gain on sale of other real estate owned and valuation adjustments, net	(45)	0
Stock-based compensation expense	1,155	604
Unrealized gain on equity investments, net	0	(668)
Deferred income tax expense (benefit)	11,052	(3,020)
Decrease (increase) in accrued interest receivable	1,176	(1,040)
Decrease (increase) in other assets	1,569	10,913
Origination of loans held for sale	(246,127)	(167,485)
Proceeds from sales of loans held for sale	275,181	163,415
(Increase) decrease in value of bank owned life insurance	(204)	201
Increase in capitalized interest, net	(911)	(1,024)
Increase in accrued interest payable	2,703	2,694
(Decrease) increase in other liabilities	(207)	352
Net cash provided by operating activities	69,650	62,422
Investing activities:
Repayments, maturities and calls of investment securities held-to-maturity	8,030	3,535
Sale of investment securities available-for-sale	9,332	30,641
Purchases of investment securities available-for-sale	(748,317)	(162,826)
Repayments of investment securities available-for-sale	185,002	83,532
Net decrease (increase) in loans	481,294	(59,232)
Purchases of stock of Federal Home Loan Bank of Pittsburgh	0	(145,399)
Redemptions of stock of Federal Home Loan Bank of Pittsburgh	265	132,509
Sales of other real estate owned	1,148	131
Investment in premises and equipment	(1,270)	(2,531)
Sales of premises and equipment	427	42
Net cash used in investing activities	(64,089)	(119,598)
Financing activities:
Net increase in demand and saving deposits	646,348	169,387
Decrease in time deposits	(64,861)	(84,456)
(Decrease) increase in brokered deposits	(153,386)	37,215
Receipts from FHLB advances	0	5,037,296
Repayments of FHLB advances	(6,623)	(5,030,000)
Receipts from federal funds purchased	0	7,665,475
Repayments of federal funds purchased	0	(7,760,475)
Cash dividend	(5,699)	(6,160)
Issuance of common stock including proceeds from exercise of common stock options	115	991
Repurchases of common shares	(12,029)	(38,739)
Net cash provided by (used in) financing activities	403,865	(9,466)
Increase (decrease) in cash, cash equivalents, and restricted cash	409,426	(66,642)
Cash, cash equivalents, and restricted cash at beginning of period	1,654,735	571,752
Cash, cash equivalents, and restricted cash at end of period	2,064,161	505,110
Supplemental disclosure of cash flow information:
Interest	4,393	15,011
Income taxes	2,572	792
Non-cash information:
Loans transferred to other real estate owned	376	2,350
Loans transferred to portfolio from held-for-sale at fair value	5,149	6,399
Allowance for credit losses on held-to-maturity debt securities	5
Allowance for credit losses	204,818	$ 139,073
Retained earnings	$ 1,036,797
Accounting standards update, extensible list	ASC 326	us-gaap:AccountingStandardsUpdate201602Member
Cumulative change in accounting principle | ASC 326
Non-cash information:
Allowance for credit losses on held-to-maturity debt securities		$ (8)
Allowance for credit losses		(35,855)
Deferred tax assets		8,461
Allowance for credit losses on unfunded lending commitments		(2,966)
Retained earnings		$ 30,368