Stockholders' Equity and Non-controlling Interests - Equity awards and units outstanding (Details) - shares	Sep. 30, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Equity awards and units outstanding	31,980	35,176
Restricted Stock Awards
Class of Stock [Line Items]
Equity awards and units outstanding	350	299
Common Units
Class of Stock [Line Items]
Equity awards and units outstanding	1,904	4,582
Common stock
Class of Stock [Line Items]
Equity awards and units outstanding	29,726	30,295

The number of each class of partnership units outstanding at the balance sheet date. Units represent shares of ownership of the general, limited, and preferred partners.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04.16(a))
-URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04.16(b))
-URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB TOPIC 4.F)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Name:	us-gaap_PartnersCapitalAccountUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant