Derivatives - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Derivative [Line Items]
Mark-to-Market Loss on Settled Swaps		$ 12,990
2014 Swaps
Derivative [Line Items]
Debt Instrument, Term	7 years
Debt Instrument, Face Amount	$ 200,000
Debt instrument, LIBOR Rate	one month LIBOR
Swaps, Number of Instruments Held	4
Swaps, Notional Amount	$ 200,000
Swaps, Average Fixed Interest Rate	2.29%
2015 Swaps
Derivative [Line Items]
Debt Instrument, Term	7 years
Debt Instrument, Face Amount	$ 260,000
Debt instrument, LIBOR Rate	one month LIBOR
Swaps, Number of Instruments Held	6
Swaps, Notional Amount	$ 260,000
Swaps, Average Fixed Interest Rate	1.79%
Settled Swaps
Derivative [Line Items]
Debt instrument, LIBOR Rate	three month LIBOR
Swaps, Number of Instruments Held	3
Swaps, Notional Amount	$ 220,000
Settlement Payment on Settled Swaps			$ 11,546