Transactions With Related Parties (Details) (USD $) In Millions	12 Months Ended
Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Transactions with Related Parties (Textuals) [Abstract]
Fees received for providing asset and property management service			$ 0.3
Amount Incurred For leased office space	$ 2.7	$ 3.0	$ 2.9

Revenues, net of returns and allowances, realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 57
-Paragraph 2
-Subparagraph c

Name:	us-gaap_RelatedPartyTransactionRevenuesFromTransactionsWithRelatedParty
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration