Financial Instruments - Information Regarding Swaps (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Derivative [Line Items]
Aggregate Notional Amount of Interest Rate Derivatives	$ 530.4	$ 631.4
Other Assets [Member]
Derivative [Line Items]
Asset	1.6	2.8
Accounts Payable [Member]
Derivative [Line Items]
Liability	(4.3)	(6.0)
Interest Rate Swaps One [Member]
Derivative [Line Items]
Maturity Date	Jun. 28, 2014
Counterparty Pays Variable Rate	1 Month LIBOR
Fixed Rate	1.00%
Asset		0
Liability		(0.4)
Interest Rate Swaps Two [Member]
Derivative [Line Items]
Maturity Date	Jun. 01, 2015
Aggregate Notional Amount of Interest Rate Derivatives	50.0
Counterparty Pays Variable Rate	1 Month LIBOR
Fixed Rate	0.60%
Asset	0	0
Liability	(0.1)	(0.2)
Interest Rate Swaps Three [Member]
Derivative [Line Items]
Maturity Date	Jul. 01, 2015
Aggregate Notional Amount of Interest Rate Derivatives	100.0
Counterparty Pays Variable Rate	1 Month LIBOR
Fixed Rate	0.50%
Asset	0	0
Liability	(0.3)	(0.4)
Interest Rate Swaps Four [Member]
Derivative [Line Items]
Maturity Date	Sep. 01, 2017
Aggregate Notional Amount of Interest Rate Derivatives	80.4
Counterparty Pays Variable Rate	1 Month LIBOR
Fixed Rate	2.80%
Asset	0	0
Liability	(3.9)	(5.0)
Interest Rate Swaps Five [Member]
Derivative [Line Items]
Maturity Date	Jan. 02, 2018
Aggregate Notional Amount of Interest Rate Derivatives	100.0
Counterparty Pays Variable Rate	1 Month LIBOR
Fixed Rate	0.90%
Asset	1.2	1.4
Liability	0	0
Interest Rate Swaps Six [Member]
Derivative [Line Items]
Maturity Date	Feb. 01, 2019
Aggregate Notional Amount of Interest Rate Derivatives	100.0
Counterparty Pays Variable Rate	1 Month LIBOR
Fixed Rate	1.60%
Asset	0	0.5
Liability	0	0
Interest Rate Swaps Seven [Member]
Derivative [Line Items]
Maturity Date	Feb. 01, 2019
Aggregate Notional Amount of Interest Rate Derivatives	100.0
Counterparty Pays Variable Rate	1 Month LIBOR
Fixed Rate	1.50%
Asset	0.4	0.9
Liability	$ 0	$ 0