Investments and Marketable Securities - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]
Changes in unrealized gains and losses on available-for- sale securities, net of tax, recorded in accumulated other comprehensive income (loss)	$ 0
Foreign cash and investments	166,000	$ 268,000
Cash and cash equivalents	$ 192,000	$ 394,000	$ 63,000	$ 65,000