Customer Concentration (Total Revenues by Geographic Area) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Concentration Risk [Line Items]
Revenues	$ 66,492	$ 53,638	$ 21,047	$ 103,124	$ 178,058	$ 124,618	$ 138,066	$ 149,706	$ 244,301	$ 590,448	$ 581,225
UNITED STATES
Concentration Risk [Line Items]
Revenues									157,327	339,596	334,325
Europe [Member]
Concentration Risk [Line Items]
Revenues									82,534	250,852	246,825
Other geographic location [Member]
Concentration Risk [Line Items]
Revenues									$ 4,440	$ 0	$ 75