Derivative Instruments - Effect of Interest Rate Swaps on Consolidated Statements of Comprehensive Income Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Effect of Derivatives on Statement of Operations and Comprehensive Income:
Realized gains (losses) on interest rate swaps	$ (158,239)	[1],[2]	$ (260,435)	[1],[2]
Realized gain (losses) on termination of interest rate swaps	(226,462)		(6,842)
Unrealized gains (losses) on interest rate swaps	$ (466,202)		$ (348,942)

[1] Interest expense related to the Company's interest rate swaps is recorded in Realized gains (losses) on interest rate swaps on the Consolidated Statements of Comprehensive Income (Loss).

[2] Consists of interest expense on interest rate swaps.