Commitments And Contingencies (Other Contingencies) (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		3 Months Ended					6 Months Ended		6 Months Ended
	Jun. 30, 2012	Mar. 31, 2007	Dec. 31, 2011 Environmental Claims For A Site In Goodyear Arizona	Dec. 31, 2008 Environmental Claims For A Site In Goodyear Arizona	Jun. 30, 2012 Environmental Claims For A Site In Goodyear Arizona	Dec. 31, 2007 Environmental Claims For A Site In Goodyear Arizona	Jul. 31, 2006 Environmental Claims For A Site In Goodyear Arizona	Jun. 30, 2012 Environmental Claims For Crab Orchard National Wildlife Refuge Superfund Site acre	Jan. 08, 2010 Merrimac Securities Class Action Lawsuit	Jun. 30, 2012 Negligence Lawsuit Rising From Fire Damage LegalMatter	Jun. 30, 2012 Environmental Claims For Site In Roseland New Jersey Home Person	Apr. 15, 2011 Environmental Claims For Site In Roseland New Jersey Person
Loss Contingencies [Line Items]
Estimated liability				$ 65.2	$ 57.6	$ 41.5
Amount of additional remediation activities			30.3	24.3
Accrued environmental loss contingencies current					16.0
Loss contingency reimbursement rate							21.00%
Other receivables					12.7
Approximate size of referenced site, acres								55,000
Stock price per share									$ 16.00
Number of separate lawsuits consolidated into one lawsuit										5
Estimate of lost profits, currently in excess										260
Approximate number of homes tested for contaminants											40
Number of homes where contaminants were found											3
Number of tenants who filed a separate lawsuit												1
Number of members in the purported class											142
Airplane operating lease period, years	7 years
Fair value of residual value guarantee	2.9	14.1
Operating lease, fair value, commitment		$ 22.1