Schedule II - Valuation and Qualifying Accounts (Details) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 15,354	$ 7,599	$ 45,516
Additions: Charges to expense	6,089	391	6,873
Deductions	(75)	(664)	(42,417)
Other changes	(169)	8,028	(2,373)
Balance at end of period	$ 21,199	$ 15,354	$ 7,599