Long-Term Debt - Summary of Long-Term Debt (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total long-term debt	$ 386,642	$ 404,612
Less current portion	(6,885)	(5,734)
Long-term debt, net of current portion	379,757	398,878
Total long-term debt	386,642	404,612
Revolving Credit Facility, Due Mar. 2020 [Member]
Debt Instrument [Line Items]
Total long-term debt	80,030
Total long-term debt	80,030
Revolving Credit Facility, Due Nov. 2016 [Member]
Debt Instrument [Line Items]
Total long-term debt		90,555
Total long-term debt		90,555
5.375% Notes, Due Oct. 2020 [Member]
Debt Instrument [Line Items]
Total long-term debt	250,000	250,000
Total long-term debt	250,000	250,000
2.40% Term Loan, Due Jun. 2022 [Member]
Debt Instrument [Line Items]
Total long-term debt	10,742	12,155
Total long-term debt	10,742	12,155
2.05% Term Loan, Due Mar. 2023 [Member]
Debt Instrument [Line Items]
Total long-term debt	45,870	51,902
Total long-term debt	$ 45,870	$ 51,902