Long Term Debt - Advances and Repayments (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Credit Facilities [Line Items]      
Advances on revolving credit facility $ 1,446,000 $ 958,355 $ 496,500
Payments on revolving credit facilities (1,137,000) (1,565,537) (226,819)
OLLC Revolving Credit Facility [Member]      
Credit Facilities [Line Items]      
Advances on revolving credit facility 1,446,000 941,000 293,000
Payments on revolving credit facilities (1,137,000) (1,209,000) (42,000)
Previous Owners Revolving Credit Facility [Member]      
Credit Facilities [Line Items]      
Advances on revolving credit facility   17,355 203,500
Payments on revolving credit facilities   $ (356,537) $ (184,819)