Allowance for Losses (Details Textual) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Losses (Textual) [Abstract]
Allowances for trade receivables	$ (6.4)	$ (6.4)	$ (6.1)
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Allowance for Losses (Textual) [Abstract]
Allowances for trade receivables	$ (6.4)	$ (6.4)
Allowances for trade receivables as percentage of rent and other receivables	7.30%	7.70%

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 210
-Section S99
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-Subparagraph (SX 210.9-03.7(d))
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant