Net amount recognized for aggregate assets, including goodwill, in excess of or less than the aggregate liabilities assumed (also referred to as net assets acquired). This amount may also be viewed as incremental amount of equity that the consolidated entity (including the portion attributable to a noncontrolling interest) will recognize as a result of the business combination.

No definition available.

Name:	us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Borrowing Arrangements (Details 5) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 ASLG	Jan. 23, 2013 ASLG Subsequent Event
Debt instruments
Number of communities under capital lease			8
Net assets held under capital leases	$ 215.0	$ 224.7
Acquired facilities, aggregate consideration				$ 145.0