Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Operating activities:
Net income	$ 10,467,000	$ 9,284,000	$ 30,411,000	$ 27,541,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	1,250,000		2,500,000		$ 750,000
Depreciation, amortization and accretion, net			8,016,000	5,088,000
Deferred income tax expense (benefit)	(767,000)	155,000	(320,000)	1,326,000
Gain on sales of mortgage loans held for sale			(1,825,000)	(1,611,000)
Origination of mortgage loans held for sale			(91,195,000)	(90,997,000)
Proceeds from sale of mortgage loans held for sale			93,861,000	90,816,000
Bank owned life insurance income	(216,000)	(222,000)	(657,000)	(670,000)
Loss on the disposal of premises and equipment			163,000	3,000
Loss (gain) on the sale of other real estate			(382,000)	153,000
Stock compensation expense			1,646,000	1,561,000
Excess tax benefits from share-based compensation arrangements			(963,000)	(366,000)
Increase in accrued interest receivable and other assets			(6,145,000)	(1,049,000)
Increase in accrued interest payable and other liabilities			14,253,000	2,509,000
Net cash provided by operating activities			49,363,000	34,304,000
Investing activities:
Purchases of securities available for sale			(327,711,000)	(203,465,000)
Proceeds from sale of securities available for sale				5,934,000	5,900,000
Proceeds from maturities of securities available for sale			355,943,000	206,734,000
Net increase in loans			(191,793,000)	(90,224,000)
Purchases of premises and equipment			(5,906,000)	(3,136,000)
Proceeds from disposal of premises and equipment			53,000
Proceeds from sale of foreclosed assets			1,403,000	2,332,000
Net cash used in investing activities			(168,011,000)	(81,825,000)
Financing activities:
Net increase in deposits			18,895,000	17,951,000
Net increase in securities sold under agreements to repurchase and federal funds purchased			56,699,000	12,709,000
Proceeds from Federal Home Loan Bank advances			199,000,000	78,200,000
Repayments of Federal Home Loan Bank advances			(191,102,000)	(71,333,000)
Issuance of common stock for options and performance stock units			1,599,000	1,994,000
Excess tax benefits from share-based compensation arrangements			963,000	366,000
Common stock repurchases			(1,534,000)	(910,000)
Cash dividends paid			(11,812,000)	(10,503,000)
Net cash provided by financing activities			72,708,000	28,474,000
Net decrease in cash and cash equivalents			(45,940,000)	(19,047,000)
Cash and cash equivalents at beginning of period			103,833,000	74,241,000	74,241,000
Cash and cash equivalents at end of period	$ 57,893,000	$ 55,194,000	57,893,000	55,194,000	$ 103,833,000
Supplemental cash flow information:
Income tax payments			9,190,000	10,177,000
Cash paid for interest			3,636,000	3,640,000
Supplemental non-cash activity:
Transfers from loans to other real estate owned			$ 1,522,000	$ 1,043,000