Dispositions and Impairment	3 Months Ended
Dispositions and Impairment	Mar. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Dispositions and Impairment	Dispositions and Impairment During the three months ended March 31, 2018 and 2017, the Company disposed of its interests in various properties for an aggregate gross sale price of $62,675 and $92,756, respectively, and recognized aggregate gains on sales of properties of $22,774 and $34,193, respectively. As of March 31, 2018, the Company had no properties classified as held for sale. At December 31, 2017, the Company had one retail property classified as held for sale. Assets held for sale as of December 31, 2017 consisted of $2,827 of real estate, at cost. The Company assesses on a regular basis whether there are any indicators that the carrying value of its real estate assets may be impaired. Potential indicators may include an increase in vacancy at a property, tenant financial instability, change in the estimated holding period of the asset and the potential sale or transfer of the property in the near future. An asset is determined to be impaired if the asset's carrying value is in excess of its estimated fair value and the Company estimates that its cost will not be recovered. During the three months ended March 31, 2018 and 2017, the Company recognized aggregate impairment charges on real estate properties of $53,049 and $2,698, respectively. Included in the impairment charges recognized during the three months ended March 31, 2018, are impairment charges of $17,906 recognized on an office property in Overland Park, Kansas, and $25,433 on an unencumbered office property in Memphis, Tennessee. The Overland Park, Kansas property is encumbered at March 31, 2018 by a $32,591 non-recourse mortgage loan, which is $19,366 in excess of the property's estimated fair value. In February 2017, the Company recognized a $5,294 loan loss on the assignment of a loan receivable secured by a hospital in Kennewick, Washington.
LCIF [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Dispositions and Impairment	Dispositions and Impairment During the three months ended March 31, 2018, the Partnership disposed of its interest in an industrial property for a gross sale price of $2,300 and recognized a gain on sale of $930. During the three months ended March 31, 2017, the Partnership sold its interest in a vacant office property for a gross sale price of $4,130 and recognized an impairment charge of $2,497. The Partnership assesses on a regular basis whether there are any indicators that the carrying value of its real estate assets may be impaired. Potential indicators may include an increase in vacancy at a property, tenant financial instability, change in the estimated holding period of the asset and the potential sale or transfer of the property in the near future. An asset is determined to be impaired if the asset's carrying value is in excess of its estimated fair value and the Partnership estimates that its cost will not be recovered. During the three months ended March 31, 2018, the Partnership recognized aggregate impairment charges on real estate properties of $22,730. Included in the impairment charges recognized during the three months ended March 31, 2018, is an impairment charge of $17,906 recognized on an office property in Overland Park, Kansas. The office property is encumbered at March 31, 2018 by a $32,591 non-recourse mortgage loan, which is $19,366 in excess of the property's estimated fair value.