Subsequent Events Acquisition of Land in Houston, Texas (Details) (Joint Venture Acquisition of Property [Member], USD $) In Millions	3 Months Ended
Jun. 30, 2011
Joint Venture Acquisition of Property [Member]
Subsequent Event [Line Items]
Subsequent Event, Date	Jul. 27, 2011
Purchase Price of Land Acquired	$ 5.6

Date of subsequent event occurrence or of indication that subsequent event occurred.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

Name:	us-gaap_SubsequentEventsDate
Namespace Prefix:	us-gaap
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration