Deposits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Deposit [Line Items]
2018	$ 239,936,000
2019	110,867,000
2020	69,944,000
2021	32,208,000
2022	19,816,000
Thereafter	9,239,000
Total certificates of deposit	482,010,000
FDIC Insurance Limit	250,000
Time Deposits, $250,000 or more	137,100,000	$ 104,500,000
Deposits from certain officers, directors, and their associated companies	$ 14,900,000	$ 14,400,000
Deposit Liabilities, Collateral Issued, Description	434.6	377.9
Deposit Liabilities Reclassified as Loans Receivable	$ 897,000	$ 986,000
Retail [Member]
Deposit [Line Items]
2018	239,936,000
2019	110,867,000
2020	62,944,000
2021	32,208,000
2022	19,816,000
Thereafter	9,239,000
Total certificates of deposit	475,010,000
Brokered [Member]
Deposit [Line Items]
2020	7,000,000
Total certificates of deposit	$ 7,000,000