Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 30,450,000	$ 23,295,000
Adjustments to reconcile net income to net cash from operating activities
Depreciation and amortization	7,345,000	7,820,000
Accretion of acquired loans	(1,057,000)	(1,867,000)
Provision for loan losses	1,100,000	2,350,000
Stock-based compensation expense	1,763,000	1,431,000
Stock grants to directors for retainer fee	403,000	363,000
Proceeds from sales of mortgage loans held for sale	77,276,000	81,368,000
Origination of mortgage loans held for sale	(73,790,000)	(81,570,000)
Net gain from sales of mortgage loans held for sale	(2,703,000)	(2,875,000)
Net gain from sales and valuation write-downs of foreclosed assets	(205,000)	(199,000)
Net (gain) loss from sales and valuation write-downs of former bank premises	(78,000)	123,000
Net loss from sales and write-downs of fixed assets	97,000	67,000
Net gain from sales of available for sale securities	0	(36,000)
Earnings on bank owned life insurance	(969,000)	(2,394,000)
Net change in:
Accrued interest receivable	(1,217,000)	(1,404,000)
Other assets	(2,744,000)	(1,987,000)
Accrued interest and other liabilities	(779,000)	278,000
Net cash from operating activities	34,892,000	24,763,000
Cash flows from investing activities
Loan originations and payments, net	(138,170,000)	(172,665,000)
Purchases of securities available for sale	(35,729,000)	(50,276,000)
Proceeds from maturities, calls and repayments of securities available for sale	31,935,000	46,177,000
Proceeds from sales of securities available for sale	0	6,706,000
Proceeds from sales of foreclosed assets	597,000	772,000
Proceeds from sales of former bank premises	1,964,000	22,000
Purchases of Federal Home Loan Bank stock	(36,000)	(3,010,000)
Proceeds from bank owned life insurance cash value release and death benefits	0	2,720,000
Net purchases of premises and equipment	(5,084,000)	(4,192,000)
Net cash for investing activities	(144,523,000)	(173,746,000)
Cash flows from financing activities
Net decrease in time deposits	(50,574,000)	(49,466,000)
Net increase in all other deposits	37,019,000	163,524,000
Net decrease in securities sold under agreements to repurchase	(6,370,000)	(9,430,000)
Maturities of Federal Home Loan Bank advances	(30,000,000)	(45,000,000)
Proceeds from Federal Home Loan Bank advances	50,000,000	90,000,000
Proceeds from stock option exercises	66,000	289,000
Employee stock purchase plan	40,000	36,000
Dividend reinvestment plan	500,000	1,426,000
Payment of cash dividends to common shareholders	(11,134,000)	(8,941,000)
Net cash (for) from financing activities	(10,453,000)	142,438,000
Net change in cash and cash equivalents	(120,084,000)	(6,545,000)
Cash and cash equivalents at beginning of period	200,101,000	183,596,000
Cash and cash equivalents at end of period	80,017,000	177,051,000
Supplemental disclosures of cash flows information
Interest	15,266,000	11,064,000
Federal income tax	7,425,000	10,275,000
Noncash financing and investing activities:
Transfers from loans to foreclosed assets	670,000	839,000
Transfers from bank premises to other real estate owned	$ 296,000	$ 1,737,000