Tax Receivable Agreement Liability Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2017
Tax Receivable Agreement [Abstract]
Effective income tax rate reconciliation, at federal statutory income tax rate, percent			35.00%
Adjustment to tax receivable agreement liability	$ 30,317	$ 2,615	$ (27,702)	$ 0	$ 8,140
Tax receivable agreement, percentage of realized cash saving in tax to pass through	8500.00%		8500.00%
Deferred Tax Assets, Investment in Subsidiaries	$ 105,886		$ 105,886		$ 109,375

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from the entity's investment in its wholly-owned subsidiaries.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 25
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=96869850&loc=d3e28680-109314

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32621-109319

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32632-109319

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