Loans - Troubled Debt Restructuring (Narrative) (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($) loan	Mar. 31, 2016 USD ($) loan	Dec. 31, 2016 USD ($)
Financing Receivable, Impaired [Line Items]
Average recorded investment	$ 2,485	$ 6,008
Impaired financing receivable, related allowance	296		$ 280
Loans receivable, nonaccrual status	$ 7,758		7,237
Number of loans modified as a TDR | loan	0	0
Troubled Debt Restructuring (TDR)
Financing Receivable, Impaired [Line Items]
Average recorded investment			153
Impaired financing receivable, related allowance			34
Non Accrual | Troubled Debt Restructuring (TDR)
Financing Receivable, Impaired [Line Items]
Loans receivable, nonaccrual status			$ 153