Accumulated Other Comprehensive Income - Summary of Changes in Accumulated Other Comprehensive Income by Component (Parenthetical) (Details) - USD ($)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Amounts reclassified from accumulated other comprehensive income	$ 428,000	$ 2,212,000
Unconsolidated Joint Ventures [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Amounts reclassified from accumulated other comprehensive income	$ 0	$ 0

Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 55
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=84158357&loc=d3e1436-108581

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration