Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net income	$ 51,516	$ 47,663
Adjustments to reconcile net income to net cash provided by operating activities
Release of provision for loan losses	(485)	(580)
Depreciation and amortization	3,803	3,283
Accretion of deferred loan fees and premiums, net	(2,653)	(6,859)
Deferred income tax expense	14,129	5,118
Amortization of investment security premiums and discounts	4,669	3,277
Right-of-use asset amortization	3,272	2,862
Share-based compensation	1,623	0
Increase in cash surrender value of bank-owned life insurance	(863)	(549)
Loss (gain) on sale of securities available for sale, net	2,172	(1,164)
Amortization of gains from terminated interest rate swaps	(5,298)	(8,274)
Employee Stock Ownership Plan expense	2,626	2,080
Other	1,013	(8)
Change in:
Loans held for sale	40	(863)
Prepaid pension expense	(7,680)	838
Other assets	40,300	43,683
Other liabilities	(39,806)	(25,597)
Net cash provided by operating activities	68,378	64,910
Investing activities
Proceeds from sales of securities available for sale	232,561	23,236
Proceeds from maturities and principal paydowns of securities available for sale	362,680	214,085
Purchases of securities available for sale	(471,543)	(1,137,969)
Proceeds from maturities and principal paydowns of securities held to maturity	421	0
Purchases of securities held to maturity	(395,835)	0
Contributions to low income housing tax credit investments	(5,642)	(2,727)
Distributions from other equity investments	606	7
Net decrease (increase) in outstanding loans	99,847	(171,325)
Proceeds from life insurance policies	19,736	0
Acquisitions, net of cash and cash equivalents acquired	(5,200)	0
Purchased banking premises and equipment, net	(3,280)	(719)
Proceeds from sale of premises held for sale	8,390	736
Net cash used in investing activities	(157,259)	(1,074,676)
Financing activities
Net (decrease) increase in demand, savings, interest checking, and money market investment deposit accounts	(155,429)	840,423
Net decrease in time deposits	(80,066)	(15,332)
Net increase in borrowed funds	644	1,302
Contingent consideration paid	(63)	(41)
Payments for repurchases of common stock	(60,595)	0
Dividends declared and paid to common shareholders	(16,908)	(10,324)
Net cash provided by financing activities	(312,417)	816,028
Net (decrease) increase in cash, cash equivalents, and restricted cash	(401,298)	(193,738)
Cash, cash equivalents, and restricted cash at beginning of period	1,231,792	2,054,070
Cash, cash equivalents, and restricted cash at end of period	830,494	1,860,332
Supplemental disclosure of cash flow information
Interest paid	3,343	1,049
Income taxes	5,505	4,858
Non-cash activities
Net increase in capital commitments relating to low income housing tax credit projects	$ 530	$ 2,943