Debt and Financing Arrangements - Summary of Recognized Interest Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total interest expense	$ 6,593	$ 8,902	$ 13,124
2010 Convertible Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Total interest expense		4,559	9,068
Credit Facility [Member]
Debt Instrument [Line Items]
Total interest expense	6,585	4,320	4,033
2006 Convertible Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Total interest expense	$ 8	$ 23	$ 23