Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Liabilities:
Derivative liabilities		$ 944	$ 9,757
Assets and liabilities measured at fair value on recurring basis [Member] | Quoted Prices in Active Markets for Identical Asset (Level 1) [Member]
Assets:
Available-for-sale securities (other non-current assets)	1,236	601	572
Assets and liabilities measured at fair value on recurring basis [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Derivative assets (other current assets)	4,912	1,458
Liabilities:
Derivative liabilities		944	9,757
Assets and liabilities measured at fair value on recurring basis [Member] | Carrying Value [Member]
Assets:
Available-for-sale securities (other non-current assets)	1,236	601	572
Derivative assets (other current assets)	4,912	1,458
Liabilities:
Derivative liabilities		944	9,757
Assets and liabilities measured at fair value on recurring basis [Member] | Fair Value Measurement [Member]
Assets:
Available-for-sale securities (other non-current assets)	1,236	601	572
Derivative assets (other current assets)	4,912	1,458
Liabilities:
Derivative liabilities		$ 944	$ 9,757