Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Customer deposits and amounts due to customers	$ 1,874	$ 3,102
Dividends payable	4,513	4,478
Accrued litigation, claims and professional fees	1,737	417
Current portion of environmental reserves	1,322	1,322
Other accrued expenses	6,098	6,153
Other current liabilities, Total	$ 15,544	$ 15,472