CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flow From Operating Activities:
Net income	$ 148,600	$ 164,460	$ 159,139
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	58,673	2,800	7,227
Depreciation and amortization	11,009	9,383	8,842
Change in deferred taxes	(9,735)	4,965	3,524
Share-based compensation	4,600	4,115	3,592
Loans originated for sale	(591,057)	(511,407)	(372,791)
Proceeds from sales of loans held for sale	611,945	513,357	380,254
Gains on sales of loans held for sale	(15,817)	(6,209)	(5,025)
Gains on sales of securities available for sale	(11,895)	(4,415)	(4,269)
Increase in cash surrender of life insurance	(5,040)	(4,518)	(4,020)
Gains on life insurance benefits	(100)	(19)	(198)
Change in interest receivable	(5,047)	(4,659)	(3,751)
Change in interest payable	(3,467)	1,090	1,217
Other adjustments	12,142	9,464	6,494
Net cash provided by operating activities	204,811	178,407	180,235
Cash Flows from Investing Activities:
Net change in interest-bearing deposits	(274,042)	199,928	(1,936)
Purchases of:
Securities available for sale	(613,117)	(676,791)	(370,284)
Securities held to maturity	(699,095)	(423,385)	(30,465)
Proceeds from sales of securities available for sale	231,391	132,837	154,519
Proceeds from maturities of:
Securities available for sale	322,617	138,356	77,881
Securities held to maturity	273,229	130,502	66,129
Redemption (Purchase) of Federal Reserve and Federal Home Loan Bank stock	0	0	(763)
Net change in loans	(792,986)	(512,364)	(483,418)
Net cash and cash equivalents received in acquisition	0	10,207	0
Proceeds from the sale of other real estate owned	8,655	2,060	9,121
Proceeds from life insurance benefits	601	815	2,836
Other investing activities	(9,278)	(8,564)	804
Net cash used in investing activities	(1,552,025)	(1,006,399)	(575,576)
Net change in :
Demand and savings deposits	2,336,120	883,524	526,859
Certificates of deposit and other time deposits	(814,466)	95,913	55,204
Borrowings	573,757	599,298	1,515,526
Repayment of borrowings	(621,548)	(643,169)	(1,677,860)
Cash dividends on common stock	(56,542)	(51,276)	(41,660)
Stock issued under employee benefit plans	639	702	707
Stock issued under dividend reinvestment and stock purchase plans	1,726	1,531	1,211
Stock options exercised	115	144	1,598
Restricted shares withheld for taxes	(980)	(1,680)	(1,902)
Repurchase of common stock	(55,912)	(19,041)	0
Net cash provided by financing activities	1,362,909	865,946	379,683
Net Change in Cash and Cash Equivalents	15,695	37,954	(15,658)
Cash and Cash Equivalents, January 1	177,201	139,247	154,905
Cash and Cash Equivalents, December 31	192,896	177,201	139,247
Additional cash flow information:
Interest paid	69,848	107,598	67,870
Income tax paid	33,201	23,588	23,289
Loans transferred to other real estate owned	813	7,031	855
Fixed assets transferred to other assets	262	1,210	374
Non-cash investing activities using trade date accounting	6,183	0	6,551
Investments transferred from held to maturity to available for sale in accordance with ASU 2017-12	0	0	30,794
ROU assets obtained in exchange for new operating lease liabilities	1,601	23,529	0
Liabilities assumed in conjunction with acquisitions
Fair value of assets acquired	0	1,451,287	0
Cash received (paid) in acquisition	0	(15)	0
Less: Common stock issued	0	229,926	0
Liabilities assumed	$ 0	$ 1,221,346	$ 0