FHLBP Advances and Short-Term Borrowed Funds (Aggregate short-term borrowings) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Repurchase Agreements [Member]
Short-term Debt [Line Items]
Amount outstanding at end of year	$ 12,023	$ 11,889
Weighted average interest rate at end of year	0.20%	0.20%
Maximum amount outstanding at any month-end	$ 17,028	$ 22,360
Daily average amount outstanding	$ 14,229	$ 19,811
Weighted average interest rate for the year	0.20%	0.20%
Federal Funds Purchased [Member]
Short-term Debt [Line Items]
Amount outstanding at end of year	$ 2,372
Weighted average interest rate at end of year	1.75%
Maximum amount outstanding at any month-end	$ 2,372
Daily average amount outstanding	$ 143	$ 450
Weighted average interest rate for the year	1.22%	0.51%