Goodwill - Changes in the Carrying Value of Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 81,689	$ 81,689
Foreign currency exchange rate changes	0	0
Goodwill, Ending Balance	81,689	81,689
MVSD [Member]
Goodwill [Roll Forward]
Goodwill, Beginning Balance	77,388	77,388
Foreign currency exchange rate changes	0	0
Goodwill, Ending Balance	77,388	77,388
SISD [Member]
Goodwill [Roll Forward]
Goodwill, Beginning Balance	4,301	4,301
Foreign currency exchange rate changes	0	0
Goodwill, Ending Balance	$ 4,301	$ 4,301