Debt - 2006 Senior Unsecured Notes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified			3 Months Ended	1 Months Ended	0 Months Ended	3 Months Ended	7 Months Ended		0 Months Ended	7 Months Ended
	Dec. 31, 2013 Interest Rate Contract [Member]	Dec. 31, 2012 Interest Rate Contract [Member]	Jun. 30, 2010 Interest Rate Contract One [Member]	Oct. 31, 2011 Interest Rate Contract Two [Member]	Oct. 30, 2011 2006 Senior Unsecured Notes [Member]	Jun. 30, 2010 2006 Senior Unsecured Notes [Member]	Jul. 30, 2011 2006 Senior Unsecured Notes [Member]	Dec. 31, 2006 2006 Senior Unsecured Notes [Member]	Oct. 30, 2011 2006 Senior Unsecured Notes [Member] London Interbank Offered Rate [Member]	Jul. 30, 2011 2006 Senior Unsecured Notes [Member] London Interbank Offered Rate [Member]
Debt Instrument [Line Items]
Senior Unsecured Notes								$ 125.0
Credit facilities, periodic payments of interest							65.0
Senior notes frequency of periodic payment					Quarterly		Quarterly
Interest rate							7.871%
Debt instrument, basis spread of interest rate									2.30%	2.30%
Unsecured senior notes, year of maturity					2016-07		2016-07
Fixed rate, minimum					7.333%
Fixed rate, maximum					7.715%
Portion of debt instrument face amount						65
Fair value of the interest rate swaps	9.0	12.5
Interest rate of interest rate derivative instrument			5.507%
Maturity date of interest rate swap			July 2016	October 2016
Interest rate swap, amount fixed				$ 60
Interest rate of derivative instrument				5.675%