TDR's and Other Pertinent Information (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of Troubled Debt Restructurings and other pertinent information
TDRs on accrual status	$ 25,852	$ 27,093
TDRs on nonaccrual status	6,067	5,199
Total TDRs	31,919	32,292
Amount of specific reserves included in the allowance for loan loss associated with TDRs:	1,342	1,417
Additional commitments to lend to a borrower who has been a party to a TDR:	$ 487	$ 1,378