Borrowing Arrangements - Summary of Recognized Interest Expense on 2010 Notes and 2006 Notes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Debt Instrument [Line Items]
Amortization of deferred financing costs			$ 3,399	$ 3,111
Convertible Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Contractual coupon interest	1,590	1,590	4,771	4,771
Amortization of discount	710	659	2,104	1,954
Amortization of deferred financing costs	180	180	540	540
Total interest expense	$ 2,480	$ 2,429	$ 7,415	$ 7,265