Other Assets and Deferred Charges, Net (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred Costs And Other Assets [Line Items]
Amortization expense of deferred charges	$ 4.7	$ 6.2	$ 5.3
Unsecured Revolving Credit Facility [Member]
Deferred Costs And Other Assets [Line Items]
Accumulated amortization of deferred lease origination costs	36.3
Accumulated amortization of deferred financing costs	$ 2.9

For an unclassified balance sheet, the accumulated amortization, as of the reporting date, which represents the periodic charge to earnings of initial direct costs which have been deferred and are being allocated over the lease term in proportion to the recognition of rental income.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 25
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=123408481&loc=SL77919138-209958

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=123394419&loc=d3e40588-112709

Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 35
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123394697&loc=d3e40879-112712

Name:	us-gaap_DeferredCostsLeasingAccumulatedAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant