v2.4.0.8
Derivative Instruments - Summary of Derivative Positions (Detail) (USD $)
In Thousands, unless otherwise specified
 6 Months Ended
Jun. 30, 2013
U.S. Dollar-denominated interest rate swap 1 [Member]
  
LIBOR-Based Debt:  
U.S. Dollar-denominated interest rate swap, Interest Rate Index USD LIBOR 3 month
U.S. Dollar-denominated interest rate swap, Principal Amount $ 200,000
U.S. Dollar-denominated interest rate swap, Fair Value/Carrying Amount of Asset (Liability) (9,871)
U.S. Dollar-denominated interest rate swap, Remaining Term (years) 3 years 3 months 18 days
U.S. Dollar-denominated interest rate swap, Fixed Interest Rate 2.61%
U.S. Dollar-denominated interest rate swap 2 [Member]
  
LIBOR-Based Debt:  
U.S. Dollar-denominated interest rate swap, Interest Rate Index USD LIBOR 3 month
U.S. Dollar-denominated interest rate swap, Principal Amount 100,000
U.S. Dollar-denominated interest rate swap, Fair Value/Carrying Amount of Asset (Liability) (16,848)
U.S. Dollar-denominated interest rate swap, Remaining Term (years) 4 years 3 months 18 days
U.S. Dollar-denominated interest rate swap, Fixed Interest Rate 5.55%
U.S. Dollar-denominated interest rate swap 3 [Member]
  
LIBOR-Based Debt:  
U.S. Dollar-denominated interest rate swap, Interest Rate Index USD LIBOR 3 month
U.S. Dollar-denominated interest rate swap, Principal Amount 45,000
U.S. Dollar-denominated interest rate swap, Fair Value/Carrying Amount of Asset (Liability) $ (6)
U.S. Dollar-denominated interest rate swap, Remaining Term (years) 1 month 6 days
U.S. Dollar-denominated interest rate swap, Fixed Interest Rate 1.19%