Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands					1 Months Ended	3 Months Ended			9 Months Ended
	Aug. 10, 2015	Jul. 01, 2015	Jun. 24, 2015	Jan. 26, 2015	Jun. 30, 2013	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Future cash payments to purchase noncontrolling interest					$ 7,300
Purchase of noncontrolling interest						$ 5,000	$ 700	$ 800	$ 4,991	$ 0
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Based Restricted Share Units (in shares)	5,000	47,550	69,558	79,761
Performance Shares | Common Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential vesting common stock (shares)									605,605