Property and Equipment, Net - Depreciation Expense Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Depreciation Expense [Line Items]
Depreciation expense	$ 24,580	$ 26,950	$ 24,390
Continuing Operations [Member]
Depreciation Expense [Line Items]
Depreciation expense	24,580	26,950	24,390
Cost of Sales [Member] | Continuing Operations [Member]
Depreciation Expense [Line Items]
Depreciation expense	22,940	24,950	21,620
Selling, General and Administrative Expenses [Member] | Continuing Operations [Member]
Depreciation Expense [Line Items]
Depreciation expense	$ 1,640	$ 2,000	$ 2,770