CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows from Operating Activities
Net income	$ 71,999	$ 74,382
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	35,656	8,039
Amortization of intangible assets	7,569	6,866
Amortization of mortgage servicing rights	3,932	2,061
Depreciation and amortization of premises and equipment	9,384	8,701
Net amortization (accretion) of premium (discount) on portfolio loans	(7,015)	(8,300)
Net amortization (accretion) of premium (discount) on investment securities	6,698	4,514
Net amortization (accretion) of premium (discount) on time deposits	(662)	(1,236)
Net amortization (accretion) of premium (discount) on Federal Home Loan Bank ("FHLB") advances and other borrowings	387	216
Impairment of other real estate owned ("OREO")	43	62
Impairment of fixed assets held for sale	36
Impairment of mortgage servicing rights	604	1,822
Impairment of leases		415
Change in fair value of equity securities, net	1,234	735
(Gain) loss on equity securities		(8)
(Gain) loss on sales of debt securities, net	(1,710)	(104)
(Gain) loss on sale of loans, net	(21,357)	(11,022)
(Gain) loss on sale of OREO	47	(84)
(Gain) loss on sale of premises and equipment	198	114
(Gain) loss on life insurance proceeds	(1,256)	(1,509)
Provision for deferred income taxes	(2,730)	1,820
Stock-based and non-cash compensation	4,413	3,236
Decrease in deferred compensation		(6,781)
Increase in cash surrender value of bank owned life insurance	(3,105)	(3,144)
Mortgage loans originated for sale	(770,186)	(469,249)
Proceeds from sales of mortgage loans	771,039	437,525
Net change in operating assets and liabilities:
Decrease (increase) in other assets	(3,435)	3,412
(Decrease) increase in other liabilities	(369)	(161)
Net cash (used in) provided by operating activities	101,414	52,322
Cash Flows from Investing Activities
Purchase of equity securities	(13,123)
Purchases of debt securities available for sale	(907,094)	(296,806)
Purchase of FHLB stock		(3,700)
Proceeds from sales of equity securities	33	958
Proceeds from sales of debt securities available for sale		227,371
Proceeds from paydowns and maturities of debt securities held to maturity		14,422
Proceeds from paydowns and maturities of debt securities available for sale	477,370	366,624
Proceeds from the redemption of FHLB stock		3,720
Net cash (received) paid in acquisitions		(61,481)
Net change in loans	(439,679)	(227,069)
Cash paid for premiums on bank-owned life insurance	(120)	(3)
Purchases of premises and equipment	(3,158)	(10,746)
Proceeds from life insurance	2,512	3,915
Proceeds from disposition of premises and equipment	806	393
Capitalized expenditures on OREO		(2)
Proceeds from sale of OREO	492	2,071
Net cash (used in) provided by investing activities	(881,961)	19,667
Cash Flows from Financing Activities
Net change in deposits	740,967	243,177
Net change in federal funds purchased and securities sold under agreements to repurchase	(3,850)	(33,895)
Proceeds from other borrowings	142,634	60,000
Repayment of other borrowings	(74,000)	(4,500)
Proceeds from FHLB advances	4,000
Repayment of FHLB advances	(32,551)	(3,479)
Cash dividends paid	(36,017)	(33,579)
Purchase of treasury stock	(9,669)	(13,323)
Cash paid for withholding taxes on share-based payments	(635)	(841)
Proceeds from stock options exercised	101	169
Common stock issuance costs		(234)
Net cash (used in) provided by financing activities	730,980	213,495
Net (decrease) increase in cash and cash equivalents	(49,567)	285,484
Cash and cash equivalents, beginning of period	529,288	239,973
Cash and cash equivalents, ending of period	479,721	525,457
Cash Payments for:
Interest	41,987	51,230
Income taxes	19,395	15,205
Non-cash Investing and Financing Activities:
OREO acquired in settlement of loans	$ 2,482	2,349
Transfer of debt securities held to maturity to available for sale		$ 573,639