Selected Quarterly Financial Data (Unaudited) - Schedule of Amounts Previously Reported and Adjustments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Total revenues	$ 212,808us-gaap_RealEstateRevenueNet	$ 216,595us-gaap_RealEstateRevenueNet	$ 215,194us-gaap_RealEstateRevenueNet	$ 217,260us-gaap_RealEstateRevenueNet	$ 214,028us-gaap_RealEstateRevenueNet	$ 214,201us-gaap_RealEstateRevenueNet	$ 262,188us-gaap_RealEstateRevenueNet	$ 262,612us-gaap_RealEstateRevenueNet	$ 861,857us-gaap_RealEstateRevenueNet	$ 953,029us-gaap_RealEstateRevenueNet	$ 961,087us-gaap_RealEstateRevenueNet
Previously reported
Total revenues					198,419	198,283	246,181	242,653
Revenues from properties reclassified (to) from discontinued operations					$ 15,609	$ 15,918	$ 16,007	$ 19,959

The aggregate revenue from real estate operations during the reporting period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(e))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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