Debt and Financing Arrangements (Interest Expense) - Summary of Recognized Interest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Debt Instrument [Line Items]
Total interest expense	$ 1,840	$ 3,123	$ 7,665	$ 10,133
2010 Convertible Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Total interest expense	808	2,132	4,455	7,188
Credit Facility [Member]
Debt Instrument [Line Items]
Total interest expense	$ 1,032	$ 991	$ 3,210	$ 2,945