Earnings per Share - Calculation (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Computation of basic earnings per share [Abstract]
Net Income for Basic Earnings per Share		$ 3,523	$ 2,336
Basic Weighted Average Shares Outstanding (in shares)	[1]	18,015,368	17,361,153
Basic Earnings per Share (in dollars per share)		$ 0.20	$ 0.13
Common Class A
Computation of basic earnings per share [Abstract]
Net Income for Basic Earnings per Share		$ 3,523	$ 2,334
Basic Weighted Average Shares Outstanding (in shares)		18,015,368	17,350,367
Participating Shares of Restricted Class A Common Stock
Computation of basic earnings per share [Abstract]
Net Income for Basic Earnings per Share		$ 0	$ 2
Basic Weighted Average Shares Outstanding (in shares)		0	10,786

[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.