Derivatives - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Derivative Instruments [Line Items]
Estimate increase to interest expense	$ 4.7
Fair value of derivatives in a net liability position	(1.3)
Termination value	1.6
Interest rate swaps [Member]
Derivative Instruments [Line Items]
Number of derivative, interest rate swap agreement	12
Derivative, Weighted average interest rate	1.67%
Derivative, notional amount	328.3
Interest Rate Swap Twelve [Member]
Derivative Instruments [Line Items]
Maturity Date	Jan. 02, 2019
Settled Interest Rate Swaps [Member]
Derivative Instruments [Line Items]
Net loss	$ 4.2
Amortized period	10 years