CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating activities:
Net income	$ 222,648,000	$ 271,605,000	$ 113,320,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for (recovery of) credit losses	48,089,000	(117,087,000)	153,180,000
Depreciation of premises and equipment, net	24,152,000	15,410,000	14,999,000
Accretion of fees, premiums and discounts, net	(28,378,000)	(38,257,000)	(60,159,000)
Amortization of intangible assets	18,401,000	10,583,000	10,909,000
Amortization of right of use lease asset	17,990,000	11,844,000	12,290,000
Decrease in operating lease liability	(16,291,000)	(11,941,000)	(12,170,000)
Income from mortgage banking activities, net	(7,271,000)	(23,216,000)	(30,201,000)
Gain on sale of securities, net	0	(331,000)	(9,076,000)
Gain on sale of other real estate owned and valuation adjustments, net	(221,000)	(385,000)	(25,000)
Stock-based compensation expense	6,349,000	5,694,000	2,677,000
Unrealized gains on equity investments, net	(5,980,000)	(5,141,000)	(761,000)
Realized loss (gain) on sale of equity investment, net	0	706,000	(22,052,000)
Deferred income tax (benefit) expense	(4,005,000)	39,838,000	(32,848,000)
(Increase) decrease in accrued interest receivable	(22,151,000)	2,739,000	(6,241,000)
Increase in other assets	(58,852,000)	(46,378,000)	(18,339,000)
Origination of loans held-for-sale	(527,684,000)	(971,863,000)	(942,188,000)
Proceeds from sales of loans held-for-sale	501,186,000	991,411,000	824,134,000
Increase (decrease) in accrued interest payable	1,196,000	(714,000)	(1,653,000)
Increase (decrease) in other liabilities	315,065,000	(4,807,000)	24,675,000
Increase in value of bank-owned life insurance	(1,311,000)	(1,048,000)	(1,757,000)
Increase in capitalized interest, net	(2,078,000)	(3,014,000)	(3,572,000)
Net cash provided by operating activities	480,854,000	125,648,000	15,142,000
Investing activities:
Purchases of investment securities held to maturity	(120,868,000)	0	(6,307,000)
Repayments, maturities and calls of investment securities held to maturity	66,186,000	20,365,000	27,085,000
Sale of investment securities available-for-sale	0	14,051,000	305,812,000
Purchases of investment securities available-for-sale	(1,218,022,000)	(3,490,596,000)	(1,454,699,000)
Repayments of investment securities available-for-sale	1,015,603,000	697,480,000	606,156,000
Proceeds from bank-owned life insurance death benefit	1,437,000	0	0
Net proceeds from sale of equity investments	0	4,899,000	85,850,000
Net cash from business combinations	573,745,000	0	0
Net (increase) decrease in loans and leases	(41,324,000)	1,453,471,000	(222,138,000)
Purchases of loans held for investment	(393,159,000)	(188,076,000)	(226,953,000)
Purchases of FHLB stock	(51,518,000)	(625,000)	(145,400,000)
Redemption of FHLB stock	36,207,000	323,000	160,726,000
Sales of assets acquired through foreclosure, net	1,964,000	2,489,000	2,014,000
Sale of premise and equipment	1,191,000	427,000	69,000
Investment in premises and equipment, net	(8,809,000)	(6,576,000)	(7,159,000)
Net cash used in investing activities	(137,367,000)	(1,492,368,000)	(874,944,000)
Financing activities:
Net (decrease) increase in demand and saving deposits	(1,123,468,000)	1,760,031,000	2,501,442,000
Decrease in time deposits	(94,251,000)	(169,871,000)	(197,765,000)
Increase (decrease) in brokered deposits	61,705,000	(202,625,000)	(29,474,000)
Receipts from FHLB advances	1,873,100,000	1,000,000	5,047,424,000
Repayments of FHLB advances	(1,523,100,000)	(7,623,000)	(5,153,476,000)
Receipts from federal funds purchased	2,730,001,000	0	8,030,475,000
Repayments of federal funds purchased	(2,730,001,000)	0	(8,225,475,000)
Contribution from noncontrolling shareholders	(504,000)	0	23,000
Cash dividend	(35,746,000)	(24,242,000)	(24,369,000)
Issuance of common stock and exercise of common stock options	3,179,000	1,522,000	2,032,000
Redemption of senior debt	0	(100,000,000)	0
Issuance of senior debt, net of costs	0	0	147,780,000
Repurchase of common shares	(200,083,000)	(13,268,000)	(155,832,000)
Net cash (used in) provided by financing activities	(1,039,168,000)	1,244,924,000	1,942,785,000
(Decrease) increase in cash, cash equivalents, and restricted cash	(695,681,000)	(121,796,000)	1,082,983,000
Cash, cash equivalents, and restricted cash at beginning of period	1,532,939,000	1,654,735,000	571,752,000
Cash, cash equivalents, and restricted cash at end of period	837,258,000	1,532,939,000	1,654,735,000
Supplemental disclosure of cash flow information:
Cash paid for interest during the period	36,487,000	23,434,000	50,103,000
Cash paid for income taxes, net	58,148,000	40,691,000	72,756,000
Non-cash information:
Loans transferred to other real estate owned	630,000	1,972,000	2,674,000
Loans transferred to portfolio from held-for-sale at fair value	97,848,000	72,621,000	34,517,000
Securities transferred to held-to-maturity from available-for-sale at fair value	931,421,000	0	0
Available-for-sale securities purchased, not settled	0	34,489,000	0
Fair value of assets acquired, net of cash received	4,713,544,000	0	0
Fair value of liabilities assumed	4,379,273,000	0	0
Impact of ASC 326 Adoption:
Allowance for credit losses on held-to-maturity debt securities	10,000	4,000
Allowance for credit losses on loans and leases	151,861,000	94,507,000	228,804,000
Retained earnings	$ 1,411,243,000	1,224,614,000
Impact of ASC 326 Adoption
Impact of ASC 326 Adoption:
Accounting Standards Update [Extensible Enumeration]	Impact of ASC 326 Adoption
Cumulative change in accounting principle | Impact of ASC 326 Adoption
Impact of ASC 326 Adoption:
Allowance for credit losses on held-to-maturity debt securities	$ 0	0	(8,000)
Allowance for credit losses on loans and leases	0	0	(35,855,000)
Deferred tax assets	0	0	8,461,000
Allowance for credit losses on unfunded lending commitments	0	0	(2,966,000)
Retained earnings	$ 0	$ 0	$ 30,368,000