CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities
Net income	$ 117,079	$ 144,434
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	(4,747)	(35,000)
Depreciation, amortization and accretion, net	30,872	27,567
Deferred income tax provision	14,228	7,168
Stock-based compensation	5,747	6,779
Other losses	2,304	76
Originations of loans held for sale	(10,256)	(73,368)
Proceeds from sales of loans held for sale	9,744	85,787
Net gains on sales of loans originated for investment and held for sale	36	(2,442)
Net gains on investment securities		(102)
Change in assets and liabilities:
Net (increase) decrease in other assets	(49,614)	19,740
Net increase in other liabilities	50,351	67,557
Net cash provided by operating activities	165,744	248,196
Available-for-sale securities:
Proceeds from maturities and principal repayments	598,865	920,073
Proceeds from calls and sales	1,080	2,820
Purchases	(913,268)	(1,900,080)
Held-to-maturity securities:
Proceeds from maturities and principal repayments, held-to-maturity	137,014
Proceeds from calls	110
Purchases, held-to-maturity	(79,470)
Other investments:
Proceeds from sales	4,132	7,956
Purchases	(21,386)	(60,155)
Loans:
Net decrease (increase) in loans and leases resulting from originations and principal repayments	(168,986)	183,820
Proceeds from sales of loans originated for investment		2,200
Purchases of loans	(149,512)	(39,558)
Proceeds from bank-owned life insurance		5,628
Purchases of premises, equipment and software	(5,966)	(9,689)
Proceeds from sales of premises and equipment		1,394
Proceeds from sales of other real estate owned	176
Other	(1,744)	(2,422)
Net cash used in investing activities	(598,955)	(888,013)
Cash flows from financing activities
Net increase in deposits	785,308	1,607,392
Dividends paid	(66,363)	(67,448)
Stock tendered for payment of withholding taxes	(3,527)	(2,845)
Common stock repurchased	(7,000)	(31,928)
Net cash provided by financing activities	708,418	1,505,171
Net increase in cash and cash equivalents	275,207	865,354
Cash and cash equivalents at beginning of period	1,258,469	1,040,944
Cash and cash equivalents at end of period	1,533,676	1,906,298
Supplemental disclosures
Interest paid	8,015	14,464
Income taxes paid, net of income tax refunds	5,356	30,399
Noncash investing and financing activities:
Operating lease right-of-use assets obtained in exchange for new lease obligations	4,979	7,221
Transfers (to) from loans and leases (from) to loans held for sale		1,839
Transfers to loans and leases from loans held for sale	(834)
Obligation to fund low-income housing partnerships		$ 15,314
Transfers of securities from available-for-sale to held-to-maturity	$ 4,133,363