Other Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Assets [Abstract]
Loss Contingency, Settlement Agreement, Terms	Previously, an inactive subsidiary of the Company executed separate settlement and release agreements with two of its insurance carriers for $35.0 million, of which $21.2 million remains. The proceeds of both settlements are restricted and can only be used to pay claims and costs of defense associated with the subsidiary’s asbestos litigation.
Interest Earned, Restricted Cash	$ 100	$ 100
Payments Made, Restricted Cash	$ 762	$ 1,023	$ 760