CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows from Operating Activities
Net income	$ 88,073	$ 48,417
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	4,139	4,531
Amortization of premiums and discounts on securities, net	5,353	2,890
Amortization of operating lease right-of-use assets	3,263	3,274
Other amortization and accretion, net	(11,715)	(4,402)
Stock based compensation	7,492	5,471
Origination of loans designated for sale	(406,392)	(378,069)
Sale of loans designated for sale	438,422	335,882
Provision for credit losses	(5,479)	36,279
Deferred income taxes	3,325	(6,257)
Losses (gains) on sale of securities	73	(1,102)
Gains on sale of loans	(12,450)	(10,585)
Gains on sale and write-downs of other real estate owned	(380)	(278)
Losses on disposition of fixed assets and write-downs upon transfer of bank premises to other real estate owned	684	790
Changes in operating assets and liabilities, net of effects from acquired companies:
Net decrease (increase) in other assets	4,899	(27,735)
Net (decrease) increase in other liabilities	(14,543)	9,174
Net cash provided by operating activities	104,764	18,280
Cash Flows from Investing Activities
Maturities and repayments of debt securities available-for-sale	417,189	211,798
Maturities and repayments of debt securities held-to-maturity	103,254	53,409
Proceeds from sale of debt securities available-for-sale	57,209	96,733
Purchases of debt securities available-for-sale	(848,122)	(626,731)
Purchases of debt securities held-to-maturity	(235,077)	0
Maturities of time deposits with other banks	0	1,495
Net new loans and principal repayments	559,920	(204,282)
Purchases of loans held for investment	(236,699)	0
Proceeds from sale of other real estate owned	4,954	6,174
Additions to other real estate owned	(2,134)	(2,004)
Proceeds from sale of FHLB and Federal Reserve Bank Stock	3,945	37,697
Purchase of FHLB and Federal Reserve Bank Stock	(59)	(26,976)
Net cash from bank acquisition	98,100	71,965
Purchase of bank owned life insurance	(50,000)	0
Additions to bank premises and equipment	(1,697)	(1,373)
Net cash used in investing activities	(129,217)	(382,095)
Cash Flows from Financing Activities
Net increase in deposits	906,690	826,686
Net (decrease) increase in repurchase agreements	(14,061)	3,387
Net decrease in FHLB borrowings with original maturities of three months or less	0	(235,000)
Repayments of FHLB borrowings with original maturities of more than three months	(33,000)	(80,000)
Proceeds from FHLB borrowings with original maturities of more than three months	0	35,000
Stock based employee benefit plans	3,287	(1,221)
Dividends paid	(14,856)	0
Net cash provided by financing activities	848,060	548,852
Net increase in cash and cash equivalents	823,607	185,037
Cash and cash equivalents at beginning of period	404,088	124,531
Cash and cash equivalents at end of period	1,227,695	309,568
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	8,334	19,834
Cash paid during the period for taxes	28,200	21,712
Recognition of operating lease right-of-use assets, other than through bank acquisition	35	1,887
Recognition of operating lease liabilities, other than through bank acquisition	35	1,887
Supplemental disclosure of non-cash investing activities:
Transfer of debt securities from available-for-sale to held-to-maturity	210,805	0
Unsettled purchases of debt securities available-for-sale	8,064	0
Transfers from loans to other real estate owned	0	5,552
Transfers from bank premises to other real estate owned	$ 3,318	$ 1,289