Segment Reporting - Schedule of Assets by Geographic Segments (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Long-lived assets:
Total	$ 380,411	$ 380,750
United States [Member]
Long-lived assets:
Total	313,210	314,930
United Kingdom [Member]
Long-lived assets:
Total	4,104	4,004
Germany [Member]
Long-lived assets:
Total	59,591	58,319
Asia (Including Japan) [Member]
Long-lived assets:
Total	$ 3,506	$ 3,497