Component of Rental Income and Expense (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leases, Income Statement, Lease Revenue [Abstract]
Recognition of straight-line rents	$ 1.9us-gaap_StraightLineRent	$ 2.6us-gaap_StraightLineRent	$ 7.2us-gaap_StraightLineRent
Recognition of amortization of above and below market leases	$ 2.8	$ 2.4	$ (0.2)

Difference between actual rental income due and rental income recognized on a straight-line basis.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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