Debt and Financing Arrangements - Summary of Recognized Interest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Debt Instrument [Line Items]
Total interest expense	$ 1,526	$ 2,977
Credit Facility [Member]
Debt Instrument [Line Items]
Total interest expense	1,520	1,051
2010 Convertible Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Total interest expense		1,920
2006 Convertible Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Total interest expense	$ 6	$ 6