CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities:
Net income	$ 127,391	$ 153,148
Adjustments to reconcile net income to net cash provided by operating activities
Provision for credit losses	4,106	(45,347)
Depreciation, amortization and accretion, net	24,526	25,561
Stock-based compensation expense	7,891	2,862
Amortization of premium on securities, net	893	2,000
Accretion of discount and deferred fees on loans, net	(7,540)	(21,335)
Mortgage servicing rights fair value changes, net	(37,349)	(7,877)
Non-designated derivatives fair value changes, net	(4,046)	(723)
Originations and purchases of mortgage loans held-for-sale	(887,393)	(2,221,967)
Early buy-out exercises of mortgage loans held-for-sale guaranteed by U.S. Government Agencies, net of subsequent paydowns or payoffs	(4,065)	(24,362)
Proceeds from sales of mortgage loans held-for-sale	1,085,471	2,336,246
Bank owned life insurance (“BOLI”) income	(48)	(1,124)
Decrease (increase) in trading securities, net	209	(280)
Decrease (increase) in brokerage customer receivables, net	3,180	(1,620)
Gains on mortgage loans sold	(20,690)	(85,200)
Losses (gains) on investment securities, net	2,782	(1,154)
(Gains) losses on sales of premises and equipment, net	(9)	29
Gains on sales and fair value adjustments of other real estate owned, net	(1,038)	(604)
Decrease in accrued interest receivable and other assets, net	110,691	109,554
Increase (decrease) in accrued interest payable and other liabilities, net	53,062	(1,026)
Net Cash Provided by Operating Activities	458,024	216,781
Investing Activities:
Proceeds from maturities and calls of available-for-sale securities	119,041	595,248
Proceeds from maturities and calls of held-to-maturity securities	66,966	106,535
Proceeds from sales of available-for-sale securities	0	0
Proceeds from sales of equity securities with readily determinable fair value	18,753	1,509
Proceeds from sales and capital distributions of equity securities without readily determinable fair value	250	386
Purchases of available-for-sale securities	(996,293)	(31,524)
Purchases of held-to-maturity securities	(560,903)	(1,894,837)
Purchases of equity securities with readily determinable fair value	(23,255)	0
Purchases of equity securities without readily determinable fair value	(1,010)	(2,360)
Purchases of Federal Home Loan Bank and Federal Reserve Bank stock, net	(785)	(293)
Distributions from investments in partnerships, net	124	60
Proceeds from sales of other real estate owned	2,497	2,162
Decrease in interest-bearing deposits with banks, net	1,359,947	1,454,501
Increase in loans, net	(472,409)	(1,082,709)
Redemption of BOLI	960	0
Purchases of premises and equipment, net	(7,722)	(4,388)
Net Cash Used for Investing Activities	(493,839)	(855,710)
Financing Activities:
Increase in deposit accounts, net	123,733	780,009
Decrease in other borrowings, net	(14,928)	(6,378)
Cash payments to settle contingent consideration liabilities recognized in business combinations	0	(16,583)
Issuance of common shares resulting from the exercise of stock options, employee stock purchase plan and conversion of common stock warrants	4,829	10,410
Common stock repurchases under authorized program	0	0
Common stock repurchases for tax withholdings related to stock-based compensation	0	0
Dividends paid	(26,452)	(24,626)
Net Cash Provided by Financing Activities	87,182	742,832
Net Increase in Cash and Cash Equivalents	51,367	103,903
Cash and Cash Equivalents at Beginning of Period	411,205	322,474
Cash and Cash Equivalents at End of Period	$ 462,572	$ 426,377