Derivatives (Fair Value of Derivative Instruments) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Fair value	$ (2.4)	[1]	$ (0.1)	[1]
Interest Rate Swap One [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	25.0
Derivative, Fair value	(0.2)	[1]	(0.3)	[1]
Derivative, Interest Rate	1.10%
Derivative, Maturity Date	Jul. 31, 2016
Interest Rate Swap Two [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	28.1
Derivative, Fair value	(0.4)	[1]	(0.5)	[1]
Derivative, Interest Rate	1.38%
Derivative, Maturity Date	Jan. 02, 2017
Interest Rate Swap Three [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	34.0
Derivative, Fair value	(0.1)	[1]	0.2	[1]
Derivative, Interest Rate	3.72%
Derivative, Maturity Date	Dec. 01, 2017
Interest Rate Swap Four [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	7.6
Derivative, Fair value	0	[1]	0.1	[1]
Derivative, Interest Rate	1.00%
Derivative, Maturity Date	Jan. 01, 2018
Interest Rate Swap Five [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	55.0
Derivative, Fair value	0	[1]	0.2	[1]
Derivative, Interest Rate	1.12%
Derivative, Maturity Date	Jan. 01, 2018
Interest Rate Swap Six [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	48.0
Derivative, Fair value	0	[1]	0.2	[1]
Derivative, Interest Rate	1.12%
Derivative, Maturity Date	Jan. 01, 2018
Interest Rate Swap Seven [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	30.0
Derivative, Fair value	(0.4)	[1]
Derivative, Interest Rate	1.78%
Derivative, Maturity Date	Jan. 02, 2019
Interest Rate Swap Eight [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	20.0
Derivative, Fair value	(0.3)	[1]
Derivative, Interest Rate	1.78%
Derivative, Maturity Date	Jan. 02, 2019
Interest Rate Swap Nine [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	20.0
Derivative, Fair value	(0.3)	[1]
Derivative, Interest Rate	1.78%
Derivative, Maturity Date	Jan. 02, 2019
Interest Rate Swap Ten [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	20.0
Derivative, Fair value	(0.3)	[1]
Derivative, Interest Rate	1.79%
Derivative, Maturity Date	Jan. 02, 2019
Interest Rate Swap Eleven [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	20.0
Derivative, Fair value	(0.3)	[1]
Derivative, Interest Rate	1.79%
Derivative, Maturity Date	Jan. 02, 2019
Interest Rate Swap Twelve [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	20.0
Derivative, Fair value	$ (0.3)	[1]
Derivative, Interest Rate	1.79%
Derivative, Maturity Date	Jan. 01, 2019

[1] As of December 31, 2014 and December 31, 2013, derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy and we do not have any significant recurring fair value measurements related to derivative instruments using significant unobservable inputs (Level 3).