Income Taxes - Reconciliation Of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Total unrecognized tax benefits at January 1	$ 30,088	$ 3,071	$ 2,734
Gross increases and decreases due to acquisition of DTS	0	27,584	0
Gross increases and decreases due to tax positions taken in prior periods	2,457	139	699
Gross increases and decreases due to tax positions taken in the current period	961	264	103
Gross increases and decreases due to settlements with taxing authorities	0	0	0
Gross increases and decreases due to lapses in applicable statutes of limitations	0	(970)	(465)
Total unrecognized tax benefits at December 31	$ 33,506	$ 30,088	$ 3,071