Earnings per Share - Calculation (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Computation of basic earnings per share [Abstract]
Net Income for Basic Earnings per Share		$ 3,102	$ 3,523
Basic Weighted Average Shares Outstanding (in shares)	[1]	18,278,773	18,015,368
Basic Earnings per Share (in dollars per share)		$ 0.17	$ 0.20
Common Class A
Computation of basic earnings per share [Abstract]
Net Income for Basic Earnings per Share		$ 3,102	$ 3,523
Basic Weighted Average Shares Outstanding (in shares)		18,278,773	18,015,368
Participating Shares of Restricted Class A Common Stock
Computation of basic earnings per share [Abstract]
Net Income for Basic Earnings per Share		$ 0	$ 0
Basic Weighted Average Shares Outstanding (in shares)		0	0

[1] The Company issues restricted shares of Class A common stock and restricted Class B units that have non-forfeitable dividend rights. Under the "two-class method," these shares and units are considered participating securities and are required to be included in the computation of basic and diluted earnings per share.