Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Assets:
Derivative financial instruments	$ 0	$ 71,000
Liabilities:
Derivative financial instruments	148,000
Long-term obligations	1,623,137,000	1,662,756,000
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member]
Assets:
Derivative financial instruments
Liabilities:
Derivative financial instruments
Long-term obligations
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Derivative financial instruments		71,000
Liabilities:
Derivative financial instruments	148,000
Long-term obligations	1,355,950,000	1,397,975,000
Significant Unobservable Inputs (Level 3) [Member]
Assets:
Derivative financial instruments
Liabilities:
Derivative financial instruments
Long-term obligations	$ 267,187,000	$ 264,781,000