Loans and Allowance for Loan Losses, Non-Performing Assets, Restructured Loans Still Accruing, and Loans Contractually Past Due (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Non-performing Assets, Restructured Loans Still Accruing and Loans Contractually Past Due [Abstract]
Non-accrual loans	$ 2,322	$ 2,017	$ 3,523
Other real estate owned	1,356	1,468	1,356
Total non-performing assets	3,678	3,485	4,879
Restructured loans still accruing	4,506	5,419	5,305
Loans past due 90 or more days and still accruing	2,501		2,859
Total non-performing and other risk assets	$ 10,685	$ 10,852	$ 13,043
Allowance for loan losses to total loans	0.92%	1.01%	0.98%
Non-accrual loans to total loans	0.50%	0.44%	0.76%
Allowance for loan losses to non-accrual loans	184.28%	228.09%	128.44%
Total non-accrual loans and restructured loans still accruing to total loans	1.46%	1.63%	1.91%
Allowance for loan losses to non-accrual loans and restructured loans still accruing	62.67%	61.87%	51.26%
Total non-performing assets to total assets	0.57%	0.56%	0.78%
Student (U.S. Government Guaranteed) [Member]
Non-performing Assets, Restructured Loans Still Accruing and Loans Contractually Past Due [Abstract]
Loans past due 90 or more days and still accruing	$ 2,397	$ 1,948	$ 2,538
Other [Member]
Non-performing Assets, Restructured Loans Still Accruing and Loans Contractually Past Due [Abstract]
Loans past due 90 or more days and still accruing	$ 104	$ 0	$ 321