Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (128)		$ 3,835
Other comprehensive (loss) income	(1,899)		(5,862)
Reclassification of cumulative translation adjustment and pension obligation adjustments to earnings upon sale of European operations	2,939	$ 0	2,939	$ 0
Ending balance	912		912
Unrealized Gains on Marketable Securities, net of tax
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	2,835		6,821
Other comprehensive (loss) income	(1,923)		(5,909)
Reclassification of cumulative translation adjustment and pension obligation adjustments to earnings upon sale of European operations	0		0
Ending balance	912		912
Cumulative Translation Adjustment
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	535		567
Other comprehensive (loss) income	(12)		(44)
Reclassification of cumulative translation adjustment and pension obligation adjustments to earnings upon sale of European operations	(523)		(523)
Ending balance	0		0
Defined Benefit Pension Obligation
Increase (Decrease) in Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(3,498)		(3,553)
Other comprehensive (loss) income	36		91
Reclassification of cumulative translation adjustment and pension obligation adjustments to earnings upon sale of European operations	3,462		3,462
Ending balance	$ 0		$ 0