Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net income	$ 271,605	$ 113,320	$ 147,918
Adjustments to reconcile net income to net cash provided by operating activities:
(Recovery of) provision for credit losses	(117,087)	153,180	25,560
Depreciation of premises and equipment, net	15,410	14,999	15,852
Accretion of fees, premiums and discounts, net	(38,257)	(60,159)	(45,548)
Amortization of intangible assets	10,583	10,909	11,113
Amortization of right of use lease asset	11,844	12,290	22,850
Decrease in operating lease liability	(11,941)	(12,170)	(12,507)
Income from mortgage banking activities, net	(23,216)	(30,201)	(11,053)
Gain on sale of securities, net	(331)	(9,076)	(333)
(Gain) loss on sale of other real estate owned and valuation adjustments, net	(385)	(25)	125
Stock-based compensation expense	5,694	2,677	3,608
Unrealized gains on equity investments, net	(5,141)	(761)	(26,175)
Realized loss (gain) on sale of equity investment, net	706	(22,052)	0
Deferred income tax expense (benefit)	39,838	(32,848)	7,074
Decrease (increase) in accrued interest receivable	2,739	(6,241)	1,406
Increase in other assets	(46,378)	(18,339)	(4,676)
Origination of loans held-for-sale	(971,863)	(942,188)	(479,289)
Proceeds from sales of loans held-for-sale	991,411	824,134	406,012
(Decrease) increase in accrued interest payable	(714)	(1,653)	1,203
(Decrease) increase in other liabilities	(4,807)	24,675	30,922
Increase in value of bank-owned life insurance	(1,048)	(1,757)	(806)
Increase in capitalized interest, net	(3,014)	(3,572)	(3,390)
Net cash provided by operating activities	125,648	15,142	89,866
Investing activities:
Purchases of investment securities held to maturity	0	(6,307)	0
Repayments, maturities and calls of investment securities held to maturity	20,365	27,085	16,170
Sale of investment securities available-for-sale	14,051	305,812	618,194
Purchases of investment securities available-for-sale	(3,490,596)	(1,454,699)	(958,259)
Repayments of investment securities available-for-sale	697,480	606,156	269,697
Proceeds from bank-owned life insurance surrender	0	0	59,710
Net proceeds from sale of equity investments	4,899	85,850	0
Net cash from business combinations	0	0	76,072
Net decrease (increase) in loans and leases	1,265,395	(449,091)	201,934
Purchases of FHLB stock	(625)	(145,400)	(394,428)
Redemption of FHLB stock	323	160,726	415,771
Sales of assets acquired through foreclosure, net	2,489	2,014	3,089
Sale of premise and equipment	427	69	71
Investment in premises and equipment, net	(6,576)	(7,159)	(14,198)
Net cash (used in) provided by investing activities	(1,492,368)	(874,944)	293,823
Financing activities:
Net increase in demand and saving deposits	1,760,031	2,501,442	69,761
Decrease in time deposits	(169,871)	(197,765)	(55,400)
Decrease in brokered deposits	(202,625)	(29,474)	(156,396)
Receipts from FHLB advances	1,000	5,047,424	32,320,456
Repayments of FHLB advances	(7,623)	(5,153,476)	(32,536,246)
Receipts from federal funds purchased	0	8,030,475	32,252,775
Repayments of federal funds purchased	0	(8,225,475)	(32,215,750)
Contribution from noncontrolling shareholders	0	23	0
Cash dividend	(24,242)	(24,369)	(22,463)
Issuance of common stock and exercise of common stock options	1,522	2,032	7,755
Redemption of senior debt	(100,000)	0	0
Issuance of senior debt, net of costs	0	147,780	0
Repurchase of common shares	(13,268)	(155,832)	(97,186)
Net cash provided by (used in) financing activities	1,244,924	1,942,785	(432,694)
(Decrease) increase in cash, cash equivalents, and restricted cash	(121,796)	1,082,983	(49,005)
Cash, cash equivalents, and restricted cash at beginning of period	1,654,735	571,752	620,757
Cash, cash equivalents, and restricted cash at end of period	1,532,939	1,654,735	571,752
Supplemental disclosure of cash flow information:
Cash paid for interest during the period	23,434	50,103	74,942
Cash paid for income taxes, net	40,691	72,756	33,843
Non-cash information:
Loans transferred to other real estate owned	1,972	2,674	2,541
Loans transferred to portfolio from held-for-sale at fair value	72,621	34,517	24,862
Available-for-sale securities purchased, not settled	34,489	0	0
Fair value of assets acquired, net of cash received	0	0	5,032,156
Fair value of liabilities assumed	0	0	5,108,228
Impact of ASC 842 Adoption:
Allowance for credit losses on held-to-maturity debt securities	4	6
Allowance for credit losses on loans and leases	94,507	228,804	47,576
Retained earnings	$ 1,224,614	977,414
Impact of ASC 842 Adoption:
Impact of ASC 842 Adoption:
Accounting Standards Update [Extensible Enumeration]	Impact of ASC 842 Adoption:
Impact of ASC 326 Adoption
Impact of ASC 842 Adoption:
Accounting Standards Update [Extensible Enumeration]	Impact of ASC 326 Adoption
Cumulative change in accounting principle
Impact of ASC 842 Adoption:
Allowance for credit losses on loans and leases			35,855
Cumulative change in accounting principle | Impact of ASC 842 Adoption:
Impact of ASC 842 Adoption:
Right of use asset	$ 0	0	121,288
Lease liability	0	0	(132,346)
Cumulative change in accounting principle | Impact of ASC 326 Adoption
Impact of ASC 842 Adoption:
Allowance for credit losses on held-to-maturity debt securities	0	(8)	0
Allowance for credit losses on loans and leases	0	(35,855)	0
Deferred tax assets	0	8,461	0
Allowance for credit losses on unfunded lending commitments	0	(2,966)	0
Retained earnings	$ 0	$ 30,368	$ 0