Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		$ (103,141)
Ending Balance	$ (46,349)	(46,349)
Unrealized Gains on Marketable Securities, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	912	6,821
Other comprehensive (loss) income	4,129	(1,780)
Reclassification into earnings upon sale of European operations	0	0
Ending Balance	5,041	5,041
Cumulative Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	0	567
Other comprehensive (loss) income	0	(44)
Reclassification into earnings upon sale of European operations	0	(523)
Ending Balance	0	0
Defined Benefit Pension Obligation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	0	(3,553)
Other comprehensive (loss) income	0	91
Reclassification into earnings upon sale of European operations	0	3,462
Ending Balance	0	0
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	912	3,835
Other comprehensive (loss) income	4,129	(1,733)
Reclassification into earnings upon sale of European operations	0	2,939
Ending Balance	$ 5,041	$ 5,041