CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flow From Operating Activities:
Net income	$ 164,460	$ 159,139	$ 96,070
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	2,800	7,227	9,143
Depreciation and amortization	9,383	8,842	7,967
Change in deferred taxes	4,965	3,524	15,523
Share-based compensation	4,115	3,592	2,827
Loans originated for sale	(511,407)	(372,791)	(377,252)
Proceeds from sales of loans held for sale	513,357	380,254	387,095
Gains on sales of loans held for sale	(6,209)	(5,025)	(5,910)
Gains on sales of securities available for sale	(4,415)	(4,269)	(2,631)
Increase in cash surrender of life insurance	(4,518)	(4,020)	(3,906)
Gains on life insurance benefits	(19)	(198)	(2,671)
Change in interest receivable	(4,659)	(3,751)	(6,838)
Change in interest payable	1,090	1,217	31
Other adjustments	9,464	6,494	7,054
Net cash provided by operating activities	178,407	180,235	126,502
Cash Flows from Investing Activities:
Net change in interest-bearing deposits	199,928	(1,936)	237,936
Purchases of:
Securities available for sale	(676,791)	(370,284)	(479,045)
Securities held to maturity	(423,385)	(30,465)	(30,220)
Proceeds from sales of securities available for sale	132,837	154,519	94,165
Proceeds from maturities of:
Securities available for sale	138,356	77,881	70,846
Securities held to maturity	130,502	66,129	72,220
Redemption (Purchase) of Federal Reserve and Federal Home Loan Bank stock	0	(763)	40
Net change in loans	(512,364)	(483,418)	(670,000)
Net cash and cash equivalents received in acquisition	10,207	0	54,536
Proceeds from the sale of other real estate owned	2,060	9,121	6,584
Proceeds from life insurance benefits	815	2,836	11,655
Other investing activities	(8,564)	804	(4,047)
Net cash used in investing activities	(1,006,399)	(575,576)	(635,330)
Net change in :
Demand and savings deposits	883,524	526,859	425,742
Certificates of deposit and other time deposits	95,913	55,204	75,236
Borrowings	599,298	1,515,526	1,088,189
Repayment of borrowings	(643,169)	(1,677,860)	(1,024,166)
Cash dividends on common stock	(51,276)	(41,660)	(31,820)
Stock issued under employee benefit plans	702	707	519
Stock issued under dividend reinvestment and stock purchase plans	1,531	1,211	991
Stock options exercised	144	1,598	2,398
Restricted shares withheld for taxes	(1,680)	(1,902)	(1,283)
Repurchase of common stock	(19,041)	0	0
Net cash provided by financing activities	865,946	379,683	535,806
Net Change in Cash and Cash Equivalents	37,954	(15,658)	26,978
Cash and Cash Equivalents, January 1	139,247	154,905	127,927
Cash and Cash Equivalents, December 31	177,201	139,247	154,905
Additional cash flow information:
Interest paid	107,598	67,870	36,332
Income tax paid	23,588	23,289	22,421
Loans transferred to other real estate owned	7,031	855	8,360
Fixed assets transferred to other assets	1,210	374	6,753
Non-cash investing activities using trade date accounting	0	6,551	9,401
Investments transferred from held to maturity to available for sale in accordance with ASU 2017-12	0	30,794	0
ROU assets obtained in exchange for new operating lease liabilities	23,529	0	0
Liabilities assumed in conjunction with acquisitions
Fair value of assets acquired	1,451,287	0	1,531,397
Cash received (paid) in acquisition	(15)	0	(12)
Less: Common stock issued	229,926	0	321,431
Liabilities assumed	$ 1,221,346	$ 0	$ 1,209,954