Other Income (Loss), Net (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Income and Expense [Line Items]
Other									$ 57	$ (124)	$ 633
Other income (loss), net	$ (84)	$ 704	$ (15)	$ (388)	$ 77	$ (246)	$ 1,452	$ 30,374	217	31,657	383
Cost-method Investments [Member]
Other Income and Expense [Line Items]
Gain on sale of ownership interests in cost method partner companies									2,914	31,835	0
Impairment charges on cost method partner companies and private equity funds									$ (2,754)	$ (54)	$ (250)