Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income (loss)	$ (2,558)	$ 572	$ (2,521)	$ 2,628
Net Income Allocated to Class A Common Stock	(2,532)	566	(2,496)	2,601
Net Income Allocated to Class B Common Stock	$ (26)	$ 6	$ (25)	$ 27
Common Stock Class A [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted Average Number of Shares Outstanding, Basic	49,080	49,080	49,080	49,080
Weighted Average Number of Shares Outstanding, Diluted	49,109	49,080	49,109	49,080
Earnings Per Share, Basic and Diluted	$ (0.05)	$ 0.01	$ (0.05)	$ 0.05
Common Stock Class B [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted Average Shares Outstanding, Basic and Diluted	1,002	1,002	1,002	1,002
Earnings Per Share, Basic and Diluted	$ (0.03)	$ 0.01	$ (0.03)	$ 0.03