Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Operating activities:
Net income	$ 10,109,000	$ 9,002,000	$ 19,944,000	$ 18,257,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	750,000		1,250,000		$ 750,000
Depreciation, amortization and accretion, net			5,292,000	3,374,000
Deferred income tax expense	(732,000)	81,000	447,000	1,171,000
Gain on sales of mortgage loans held for sale			(1,103,000)	(1,133,000)
Origination of mortgage loans held for sale			(57,433,000)	(63,461,000)
Proceeds from sale of mortgage loans held for sale			58,931,000	60,104,000
Bank owned life insurance income	(220,000)	(226,000)	(441,000)	(448,000)
Gain on the disposal of premises and equipment				(5,000)
Loss (gain) on the sale of other real estate			(443,000)	165,000
Stock compensation expense			1,073,000	995,000
Excess tax benefits from share-based compensation arrangements			(520,000)	(293,000)
Decrease (increase) in accrued interest receivable and other assets			(5,246,000)	386,000
Increase (decrease) in accrued interest payable and other liabilities			12,321,000	(4,303,000)
Net cash provided by operating activities			34,072,000	14,809,000
Investing activities:
Purchases of securities available for sale			(227,714,000)	(92,730,000)
Proceeds from sale of securities available for sale				5,934,000	5,900,000
Proceeds from maturities of securities available for sale			232,825,000	184,878,000
Net increase in loans			(144,605,000)	(32,596,000)
Purchases of premises and equipment			(4,660,000)	(2,615,000)
Proceeds from sale of foreclosed assets			1,401,000	1,820,000
Net cash provided by (used in) investing activities			(142,753,000)	64,691,000
Financing activities:
Net decrease in deposits			(21,754,000)	(51,862,000)
Net increase (decrease) in securities sold under agreements to repurchase and federal funds purchased			84,588,000	(39,241,000)
Proceeds from Federal Home Loan Bank advances			160,000,000	63,200,000
Repayments of Federal Home Loan Bank advances			(160,466,000)	(61,177,000)
Issuance of common stock for options and performance stock units			1,045,000	1,566,000
Excess tax benefits from share-based compensation arrangements			520,000	293,000
Common stock repurchases			(1,083,000)	(900,000)
Cash dividends paid			(7,768,000)	(6,944,000)
Net cash provided by (used in) financing activities			55,082,000	(95,065,000)
Net decrease in cash and cash equivalents			(53,599,000)	(15,565,000)
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	$ 50,234,000	$ 58,676,000	50,234,000	58,676,000	$ 103,833,000
Supplemental cash flow information:
Income tax payments			5,490,000	6,774,000
Cash paid for interest			2,438,000	2,438,000
Supplemental non-cash activity:
Transfers from loans to other real estate owned			$ 1,511,000	$ 232,000