Shareholders' Equity / Partners' Capital - Noncontrolling Interest Activity in Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Class of Stock [Line Items]
Income (loss) allocated to noncontrolling interest	$ 1,114	$ (301)
Consolidated Subsidiaries With Noncontrolling Interest
Class of Stock [Line Items]
Income (loss) allocated to noncontrolling interest	(11)	38
Class A Units
Class of Stock [Line Items]
Income (loss) allocated to noncontrolling interest	$ 1,125	$ (339)

Amount of Net Income (Loss) attributable to noncontrolling interest.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 55
-Paragraph 4J
-URI http://asc.fasb.org/extlink&oid=84234705&loc=SL4591551-111686

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=84161450&loc=SL4573702-111684

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