Noncontrolling Interest - Contributions (Details) - USD ($) $ in Thousands		12 Months Ended	21 Months Ended
Mar. 31, 2015	Jun. 30, 2016	Dec. 31, 2016
Noncontrolling Interest [Line Items]
Ownership percentage	72.00%	92.00%
ASTC Contribution
Noncontrolling Interest [Line Items]
Contributions made	$ 1,422	$ 4,000	$ 5,422
Minority Owner Contribution
Noncontrolling Interest [Line Items]
Contributions made	$ 422	$ 0	$ 422

Amount of increase in noncontrolling interest from subsidiary issuance of equity interests to noncontrolling interest holders.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=64809438&loc=SL4573702-111684

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=68079674&loc=SL4569655-111683

Name:	us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration