Fair Value Measurements (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			1 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Jan. 31, 2014 Convertible Senior Subordinated Notes 3/4% convertible senior subordinated notes due 2023	Mar. 31, 2014 Convertible Senior Subordinated Notes 3/4% convertible senior subordinated notes due 2023	Dec. 31, 2013 Convertible Senior Subordinated Notes 3/4% convertible senior subordinated notes due 2023	Dec. 31, 2013 Cash And Cash Equivalents	Dec. 31, 2013 Marketable Securities
Financial assets							$ 1,000	$ 800
Carrying value	0		346			300
Interest rate (as a percent)					0.75%	0.75%
Repayments of Long-term Debt	$ 3,304	$ 13,000		$ 300