CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flow From Operating Activities:
Net income	$ 96,070	$ 81,051	$ 65,384
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	9,143	5,657	417
Depreciation and amortization	7,967	7,161	6,262
Change in deferred taxes	15,523	8,611	4,444
Share-based compensation	2,827	2,600	2,270
Loans originated for sale	(377,252)	(354,265)	(364,411)
Proceeds from sales of loans held for sale	387,095	367,148	367,377
Gains on sales of loans held for sale	(5,910)	(5,918)	(5,625)
Gain on the sale of insurance subsidiary			8,265
Gain on cancellation of subordinated debentures			(1,250)
Gains on sales of securities available for sale	(2,631)	(3,389)	(2,670)
Increase in cash surrender of life insurance	(3,906)	(3,630)	(2,927)
Gains on life insurance benefits	(2,671)	(643)
Change in interest receivable	(6,838)	(1,779)	(2,833)
Change in interest payable	31	18	(162)
Other adjustments	7,054	1,097	(1,351)
Net cash provided by operating activities	126,502	103,719	56,660
Cash Flows from Investing Activities:
Net change in interest-bearing deposits	237,936	7,856	24,917
Purchases of:
Securities available for sale	(479,045)	(281,470)	(200,154)
Securities held to maturity	(30,220)	(110,797)	(87,282)
Proceeds from sales of securities available for sale	94,165	167,186	83,647
Proceeds from maturities of:
Securities available for sale	70,846	73,956	63,124
Securities held to maturity	72,220	119,052	98,581
Redemption (Purchase) of Federal Reserve and Federal Home Loan Bank stock	40	19,669	7,268
Net change in loans	(670,000)	(452,781)	(350,287)
Net cash and cash equivalents received (paid) in acquisition	54,536		(7,936)
Net cash received from sale of insurance subsidiary			15,155
Proceeds from the sale of other real estate owned	6,584	9,974	12,567
Proceeds from life insurance benefits	11,655	3,141
Other investing activities	(4,047)	(4,490)	9
Net cash used in investing activities	(635,330)	(448,704)	(340,391)
Net change in :
Demand and savings deposits	425,742	332,600	240,736
Certificates of deposit and other time deposits	75,236	(66,920)	(79,656)
Borrowings	1,088,189	1,107,795	491,660
Repayment of borrowings	(1,024,166)	(982,449)	(370,813)
Cash dividends on common stock	(31,820)	(22,203)	(15,654)
Stock issued under employee benefit plans	519	462	460
Stock issued under dividend reinvestment and stock purchase plans	991	835	661
Stock options exercised	2,398	2,602	1,531
Stock redeemed	(1,283)	(1,980)	(1,640)
Net cash provided by financing activities	535,806	370,742	267,285
Net Change in Cash and Cash Equivalents	26,978	25,757	(16,446)
Cash and Cash Equivalents, beginning of the year	127,927	102,170	118,616
Cash and Cash Equivalents, end of year	154,905	127,927	102,170
Additional cash flow information:
Interest paid	36,332	26,821	24,903
Income tax paid	22,421	11,999	21,200
Loans transferred to other real estate owned	8,360	1,684	3,644
Fixed assets transferred to other assets	6,753	360	1,600
Non-cash investing activities using trade date accounting	9,401	14,179	1,559
Liabilities assumed in conjunction with acquisitions
Fair value of assets acquired	1,531,397	0	635,047
Cash received (paid) in acquisition	(12)		(14,500)
Less: Common stock issued	321,431		70,402
Liabilities assumed	$ 1,209,954	$ 0	$ 550,145