Debt and Financing Arrangements - Summary of Reconciliation of Debt (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Debt [Line Items]
Total debt	$ 91,506	$ 60,705
Less: current portion of long-term debt	14,643	22,143
Long-term debt, less current portion	76,863	38,562
Senior Notes under a Master Shelf Agreement [Member]
Debt [Line Items]
Total debt	39,643	50,715
Credit Agreement with Banks [Member]
Debt [Line Items]
Total debt	$ 51,863	$ 9,990	$ 19,400