Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating Activities
Net income	$ 96,144,000	$ 38,670,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	6,098,000	72,181,000
Depreciation of premises, furniture, and equipment	7,529,000	8,397,000
Net amortization of premium on securities	10,243,000	10,914,000
Net securities losses	0	1,005,000
Gains on sales of 1-4 family mortgages and corporate loans held-for-sale	(16,444,000)	(7,230,000)
Net losses on sales and valuation adjustments of OREO	67,000	128,000
Amortization of the FDIC indemnification asset	0	892,000
Net (gains) losses on sales and valuation adjustments of premises, furniture, and equipment	(731,000)	213,000
BOLI income	(3,481,000)	(3,798,000)
Share-based compensation expense	8,157,000	7,677,000
Tax benefit related to share-based compensation	196,000	148,000
Amortization of other intangible assets	5,605,000	5,590,000
Originations of mortgage loans held-for-sale	(468,530,000)	(297,019,000)
Proceeds from sales of mortgage loans held-for-sale	508,076,000	292,410,000
Net increase in equity securities	(36,573,000)	(1,818,000)
Net decrease (increase) in accrued interest receivable and other assets	2,347,000	(124,850,000)
Net (decrease) increase in accrued interest payables and other liabilities	(642,000)	12,871,000
Net cash provided by operating activities	118,061,000	16,381,000
Investing Activities
Proceeds from maturities, repayments, and calls of securities available-for-sale	561,493,000	497,430,000
Proceeds from sales of securities available-for-sale	0	39,095,000
Purchases of securities available-for-sale	(672,064,000)	(914,234,000)
Proceeds from maturities, repayments, and calls of securities held-to-maturity	478,000	2,467,000
Purchases of securities held-to-maturity	0	(18,000)
Net purchases of FHLB stock	10,530,000	(33,103,000)
Net increase in loans	(312,149,000)	(1,360,147,000)
Premiums paid on BOLI, net of proceeds from claims	4,045,000	2,997,000
Proceeds from sales of OREO	2,897,000	230,000
Proceeds from sales of premises, furniture, and equipment	2,757,000	0
Purchases of premises, furniture, and equipment	(3,347,000)	(4,647,000)
Net cash received from acquisition	0	142,282,000
Net cash used in investing activities	(405,360,000)	(1,627,648,000)
Financing Activities
Net increase in deposit accounts	1,020,419,000	1,456,302,000
Net (decrease) increase in borrowed funds	(246,990,000)	634,905,000
Net proceeds from the issuance of preferred stock	0	221,312,000
Repurchases of common stock	(14,929,000)	(22,557,000)
Cash dividends paid	(40,085,000)	(32,480,000)
Restricted stock activity	(2,959,000)	(3,135,000)
Net cash provided by financing activities	715,456,000	2,254,347,000
Net increase in cash and cash equivalents	428,157,000	643,080,000
Cash and cash equivalents at beginning of period	1,117,244,000	299,221,000
Cash and cash equivalents at end of period	1,545,401,000	942,301,000
Supplemental Disclosures of Cash Flow Information:
Income taxes paid	19,225,000	587,000
Interest paid to depositors and creditors	20,000,000	46,331,000
Dividends declared, but unpaid	15,821,000	15,857,000
Stock issued for acquisitions, net of issuance costs	0	71,883,000
Non-cash transfers of loans to OREO	0	121,000
Non-cash transfers of loans held-for-investment to loans held-for-sale	$ (14,157,000)
Non-cash transfers of loans held-for-investment to loans held-for-sale		$ 2,193,000