Restricted Cash (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 104,147	$ 89,879	$ 88,818	$ 81,053
Restricted Cash	20,278	21,171	21,883	22,874
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents	$ 124,425	$ 111,050	$ 110,701	$ 103,927
Loss Contingency, Settlement Agreement, Terms	The Company has restricted cash recorded in Other assets related to proceeds from an inactive subsidiary of the Company which previously executed separate settlement and release agreements with two of its insurance carriers for an original total value of $35.0 million. 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. The proceeds of the settlement and release agreements have been deposited into interest bearing accounts which earned $0.2 million and less than $0.1 million in the years ended December 31, 2018 and 2017, respectively, offset by $1.1 million and $0.8 million of net payments in 2018 and 2017, respectively.