The Company and Financial Statement Presentation (Details)	Mar. 31, 2012 states properties
The Company and Financial Statement Presentation [Abstract]
Number of Consolidated Properties	185
Number of States in which Entity has Interests	39

The number of states the entity operates in as of the balance sheet date.

No definition available.

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant