Fair Value Measurements - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 11, 2014
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Gain on the sale of an equity method investment	$ 300,000
Gain on cumulative translation reclassification adjustment associated with the equity method investee	0	(787,000)	0
Cash, fair value received	2,600,000
Equity Method Investments				2,300,000
Other than Temporary Impairment Losses, Investments	1,900,000
Available-for-sale Securities, Equity Securities	$ 4,600,000