Schedule II (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance of Deferred Tax Assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Period	$ 5,298	$ 4,143	$ 11,122
Additions Charged to Costs and Expenses / Provision Benefit	3,408	830	269
Additions Other	(173)		(7,248)
Deductions		325
Balance End of Period	8,533	5,298	4,143
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance Beginning of Period	4,134	4,123	2,989
Additions Charged to Costs and Expenses / Provision Benefit	1,123	1,164	2,635
Additions Other	0	0	19
Deductions	1,143	1,153	1,520
Balance End of Period	$ 4,114	$ 4,134	$ 4,123