Debt and Financing Arrangements (Interest Expense) - Summary of Recognized Interest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Debt Instrument [Line Items]
Total interest expense	$ 2,848	$ 3,577	$ 5,825	$ 7,010
2010 Convertible Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Total interest expense	1,683	2,534	3,609	5,041
Credit Facility [Member]
Debt Instrument [Line Items]
Total interest expense	$ 1,165	$ 1,043	$ 2,216	$ 1,969