CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities:
Net income	$ 47,055	$ 52,850
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	3,690	4,034
Amortization of intangible assets	3,732	3,351
Net accretion on securities, loans and borrowings	(4,547)	(7,127)
Stock-based compensation	1,886	1,674
Provision for credit losses	906	(5,719)
Amortization of mortgage servicing rights	109	135
Unrealized gain on equity securities	(2)	(24)
Income from bank-owned life insurance policies	(440)	(480)
Net gain on sale of loans and other assets	(450)	(280)
Change in other assets and other liabilities	(1)	13,396
Net cash provided by operating activities	51,938	61,810
Investing activities:
Proceeds from maturities, calls and paydowns of available-for-sale investment securities	49,667	78,112
Proceeds from maturities and redemptions of equity and other investment securities	460	2,383
Purchases of available-for-sale investment securities	(1,256,723)	(546,733)
Purchases of equity and other securities	(37)	(10)
Net (increase) decrease in loans	(49,556)	52,297
Cash paid for acquisitions, net of cash acquired of $0, and $0, respectively	(2,464)	0
Purchases of premises and equipment, net	(2,214)	(876)
Real estate tax credit investments	(247)	(155)
Net cash used in investing activities	(1,261,114)	(414,982)
Financing activities:
Net increase in deposits	406,499	979,263
Net decrease in borrowings	(24,213)	(26,940)
Payments on subordinated debt held by unconsolidated subsidiary trusts	0	(77,320)
Issuance of common stock	485	7,329
Purchases of treasury stock	(3,592)	(68)
Increase in deferred compensation arrangements	63	68
Cash dividends paid	(23,235)	(22,553)
Withholding taxes paid on share-based compensation	(969)	(1,065)
Net cash provided by financing activities	355,038	858,714
Change in cash and cash equivalents	(854,138)	505,542
Cash and cash equivalents at beginning of period	1,875,064	1,645,805
Cash and cash equivalents at end of period	1,020,926	2,151,347
Supplemental disclosures of cash flow information:
Cash paid for interest	2,839	4,351
Cash paid for income taxes	3,344	2,701
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	23,234	22,671
Transfers from loans to other real estate	$ 203	$ 63