Summary of Significant Accounting Policies and Recent Accounting Pronouncements - Accumulated Other Comprehensive Loss (Components Of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation adjustment	$ 5,525	$ (11,545)	$ (6,908)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(46,475)	86,376	138,948
Other comprehensive loss	5,523	(11,317)	(7,220)
Ending Balance	(82,246)	(46,475)	86,376
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(22,333)	(10,788)	(3,880)
Other comprehensive loss		(11,545)	(6,908)
Ending Balance	(16,808)	(22,333)	(10,788)
Change in unrealized gain/loss on available-for-sale securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	2	(226)	86
Other comprehensive loss		228	(312)
Ending Balance	0	2	(226)
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation adjustment	5,525	(11,545)	(6,908)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(22,331)	(11,014)	(3,794)
Other comprehensive loss	5,523	(11,317)	(7,220)
Ending Balance	$ (16,808)	$ (22,331)	$ (11,014)