Subordinated Debentures (Details) $ / shares in Units, $ in Thousands		9 Months Ended	12 Months Ended
	Nov. 15, 2008 USD ($) Offering $ / shares shares	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) Quarter	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Subordinated note outstanding			$ 20,619	$ 24,119
Subordinated Note, original principal amount		$ 3,500
Series A Preferred Stock [Member]
Debt Instrument [Line Items]
Aggregate preferred stock outstanding	$ 3,500		4	$ 4
Junior Subordinated Debt Securities [Member]
Debt Instrument [Line Items]
Junior subordinated debt securities principal amount			$ 20,619
Floating rate of interest			3-month LIBOR (0.88% December 31, 2016)
Debt instrument base rate			0.88%
Basis points			2.00%
Maturity date			Jan. 07, 2035
Proceeds from issuance of debentures			$ 17,000
Number of consecutive quarterly periods | Quarter			20
Series A Subordinated Notes [Member]
Debt Instrument [Line Items]
Number of private placement offering | Offering	70
Private placement offering price (per unit) | $ / shares	$ 100,000
Gross proceeds of private placement	$ 7,000
Number of shares consisted in each unit (in shares) | shares	6,250
Subordinated note outstanding	$ 3,500
Payment for subordinated notes outstanding		$ 3,500
Annual interest rate on subordinated notes		8.00%
Subordinated Note, original principal amount	$ 50
Severn Capital Trust I [Member]
Debt Instrument [Line Items]
Common equity owned			100.00%