Summary of Company's Interest Rate Derivatives (Parenthetical) (Detail) - Derivatives not designated as hedging instruments	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
LIBOR
Derivatives, Fair Value [Line Items]
LIBOR floor	1.00%	1.00%
Interest Rate Swap L
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	3.44%	3.44%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap M
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	3.43%	3.43%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap N
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	3.37%	3.37%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap O
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	3.19%	3.19%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap P
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	3.08%	3.08%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap Q
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	2.99%	2.99%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap R
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	2.98%	2.98%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap S
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	2.73%	2.73%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap T
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	2.74%	2.74%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap U
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	2.66%	2.66%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap V
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	2.60%	2.60%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap W
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	2.40%	2.40%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08
Interest Rate Swap X
Derivatives, Fair Value [Line Items]
Derivative, Fixed Interest Rate	2.25%	2.25%
Derivative, Maturity Date, Range Start	2016-08
Derivative, Maturity Date, Range End	2019-08