Investments In Real Estate (Narrative) (Details) (Subsequent Event [Member], 6 Braham Street [Member]) In Millions, unless otherwise specified	0 Months Ended
Apr. 07, 2014 USD ($)	Apr. 07, 2014 GBP (£)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received on sale of property	$ 41.5	£ 25.0
Sale proceeds after costs and various tenant prepayments	37.5	22.6
Net gain on sale of discontinued operation	$ 15.8	£ 9.5

Amount of difference between the carrying amount and the sales price of real estate properties sold as part of discontinued operations.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration