Financial Instruments - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended
	Nov. 01, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financial Instruments and Fair Value [Line Items]
Available-for-sale securities, realized gain			$ 1,000,000	$ 1,400,000	$ 2,700,000
Fair market value of investments with unrealized losses		241,760,000	241,760,000	59,100,000
Fair market value of investments with unrealized losses greater than one year		600,000	600,000
Fair market value of investments with unrealized losses less than one year		241,200,000	241,200,000
Gain (loss) on foreign currency transactions			(6,900,000)	(4,500,000)	900,000
Realized gains (losses) on foreign currency contracts			5,900,000	4,000,000	(1,300,000)
Proceeds from sale of equity interest	34,200,000		34,212,000
Additional proceeds held in escrow	5,200,000
Amount of gain will record		34,200,000
Foreign Exchange Contract
Financial Instruments and Fair Value [Line Items]
Gain (loss) on foreign currency transactions			$ 200,000	$ 100,000