Loans and Allowance for Loan Losses - Impaired Loans (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016 USD ($) item	Mar. 31, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) item loan	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Impaired loans by class
Impaired Loans with Specific Allowance, Recorded Investment	$ 6,273			$ 6,273		$ 11,137
Impaired Loans with Specific Allowance, Related Allowance	1,596			1,596		1,013
Impaired Loans with No Specific Allowance, Recorded Investment	6,998			6,998		4,238
Total Impaired Loans, Recorded Investment	13,271			13,271		15,375
Total Impaired Loans, Unpaid Principal Balance	15,349			15,349		16,750
Impaired loans, additional information
Loan Chargeoff Expense				535
Average recorded investment in impaired loans and related interest income recognized
Average investment in impaired loans	14,281		$ 13,883	12,054	$ 14,222
Interest income recognized on an accrual basis on impaired loans	74		61	149	123
Interest income recognized on a cash basis on impaired loans	76		53	$ 136	107
Total Recorded Investment in Impaired Financing Receivables [Member] | Credit Concentration Risk [Member]
Impaired loans, additional information
Impaired loans outstanding balance, decrease	$ 2,100
Concentration Risk, Percentage	14.00%
Number of loans causing change in Impaird loan | item				4
Total Recorded Investment in Impaired Financing Receivables [Member] | Government Contracts Concentration Risk [Member]
Impaired loans by class
Total Impaired Loans, Recorded Investment	$ 5,000			$ 5,000
Commercial
Impaired loans by class
Impaired Loans with Specific Allowance, Recorded Investment	5,894			5,894		9,961
Impaired Loans with Specific Allowance, Related Allowance	1,338			1,338		708
Impaired Loans with No Specific Allowance, Recorded Investment	6,207			6,207		4,216
Total Impaired Loans, Recorded Investment	12,101			12,101		14,177
Total Impaired Loans, Unpaid Principal Balance	14,171			14,171		15,552
Average recorded investment in impaired loans and related interest income recognized
Average investment in impaired loans	13,020		12,908	10,781	13,244
Interest income recognized on an accrual basis on impaired loans	69		56	138	112
Interest income recognized on a cash basis on impaired loans	67		53	121	104
Impaired loans, recorded investment, in process of foreclosure	611			611
Commercial Business
Impaired loans by class
Impaired Loans with Specific Allowance, Recorded Investment	1,565			1,565		574
Impaired Loans with Specific Allowance, Related Allowance	613			613		4
Impaired Loans with No Specific Allowance, Recorded Investment	3,390			3,390		3,260
Total Impaired Loans, Recorded Investment	4,955			4,955		3,834
Total Impaired Loans, Unpaid Principal Balance	4,955			$ 4,955		3,834
Impaired loans, additional information
Number of loans causing change in Impaird loan | item				2
Recorded Investment on impaired loans	1,000			$ 1,000
Average recorded investment in impaired loans and related interest income recognized
Average investment in impaired loans	3,843		3,228	3,553	3,369
Interest income recognized on an accrual basis on impaired loans	39		39	78	78
Interest income recognized on a cash basis on impaired loans	39		39	65	75
Commercial Real Estate
Impaired loans by class
Impaired Loans with Specific Allowance, Recorded Investment	3,905			3,905		7,587
Impaired Loans with Specific Allowance, Related Allowance	633			633		513
Impaired Loans with No Specific Allowance, Recorded Investment	282			282
Total Impaired Loans, Recorded Investment	4,187			4,187		7,587
Total Impaired Loans, Unpaid Principal Balance	4,780			4,780		7,587
Impaired loans, additional information
Repurchased by selling financial institution		$ 5,000
Impaired Financing Receivable Repurchase Decrease		5,000
Impaired loans, due to extended stabilization and interest only period, as well as lack of project specific cash flows		1,800
Impaired loans, participation		651
Impaired loans decrease, significant net effect		2,700
Impaired loans decrease, other factors net effect				$ 600
Number of Impaired Loans Effect of Other Factors | item				9
Impaired Loan Finance Receivable				$ 760
Impaired Loan Finance Receivable Balance				266
Impaired loans, partial charge-off and loan amortization		$ 224
Impaired Foreclosure Loan				127
Average recorded investment in impaired loans and related interest income recognized
Average investment in impaired loans	6,526		6,533	4,542	6,538
Interest income recognized on an accrual basis on impaired loans	28		15	56	30
Interest income recognized on a cash basis on impaired loans	25		12	50	25
Acquisition & Development
Impaired loans by class
Impaired Loans with Specific Allowance, Recorded Investment	424			424		1,800
Impaired Loans with Specific Allowance, Related Allowance	92			92		191
Impaired Loans with No Specific Allowance, Recorded Investment	2,535			2,535		956
Total Impaired Loans, Recorded Investment	2,959			2,959		2,756
Total Impaired Loans, Unpaid Principal Balance	4,436			4,436		4,131
Average recorded investment in impaired loans and related interest income recognized
Average investment in impaired loans	2,651		3,147	2,686	3,337
Interest income recognized on an accrual basis on impaired loans	2		2	4	4
Interest income recognized on a cash basis on impaired loans	3		2	6	4
Residential
Impaired loans by class
Impaired Loans with Specific Allowance, Recorded Investment						1,045
Impaired Loans with Specific Allowance, Related Allowance						276
Impaired Loans with No Specific Allowance, Recorded Investment	763			763		22
Total Impaired Loans, Recorded Investment	763			763		1,067
Total Impaired Loans, Unpaid Principal Balance	768			$ 768		1,067
Impaired loans, additional information
Concentration Risk, Percentage				77.00%
Number of impaired loans, increase related | loan				6
Average recorded investment in impaired loans and related interest income recognized
Average investment in impaired loans	865		946	$ 962	948
Interest income recognized on an accrual basis on impaired loans	5		5	10	10
Interest income recognized on a cash basis on impaired loans	$ 9			$ 14	2
Number of loans, in process of foreclosure | item	3			3
Impaired loans, recorded investment, in process of foreclosure	$ 271			$ 271
Home Equity
Impaired loans by class
Impaired Loans with Specific Allowance, Recorded Investment						28
Impaired Loans with Specific Allowance, Related Allowance						28
Impaired Loans with No Specific Allowance, Recorded Investment	28			28
Total Impaired Loans, Recorded Investment	28			28		28
Total Impaired Loans, Unpaid Principal Balance	28			28		28
Average recorded investment in impaired loans and related interest income recognized
Average investment in impaired loans	28		28	28	28
Interest income recognized on an accrual basis on impaired loans				1	1
Interest income recognized on a cash basis on impaired loans				1	1
Consumer
Impaired loans by class
Impaired Loans with Specific Allowance, Recorded Investment	379			379		103
Impaired Loans with Specific Allowance, Related Allowance	258			258		1
Total Impaired Loans, Recorded Investment	379			379		103
Total Impaired Loans, Unpaid Principal Balance	382			382		$ 103
Average recorded investment in impaired loans and related interest income recognized
Average investment in impaired loans	$ 368		$ 1	$ 283	$ 2