Long-Term Debt (Details) - USD ($) $ in Thousands				1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Nov. 20, 2014	Dec. 12, 2013	Mar. 21, 2013	Dec. 31, 2013	Oct. 31, 2012	Dec. 31, 2014	Jun. 30, 2015	Sep. 30, 2014	Jul. 31, 2015	Oct. 17, 2012	Oct. 01, 2010
Long-Term Debt
Total Long-term Debt							$ 2,111,807	$ 2,099,748
Less: current portion								(261)
Long-term debt, net of current portion							2,111,807	2,099,487
Adjustment made due to new guidance
Adjustments
Long-term debt								(58,600)
Other assets								(41,285)
Other current assets								(17,315)
Parent Company
Long-Term Debt
Consent fee				$ 18,560						$ 17,345
Dividend paid				$ 445,537	$ 721,682
Term loan B-2
Long-Term Debt
Principal amount							1,507,500	1,507,500
Net unamortized premium (discount) on Holdco Notes							(34,731)	(45,539)
Total Long-term Debt							$ 1,472,769	1,461,961
Face amount of debt			$ 1,507,500
Portion of excess cash flow (as defined) as part of additional prepayments on term loan (as a percent)							50.00%
Term loan B-2 | Eurodollar (LIBOR)
Long-Term Debt
Floor for reference rate (as a percent)							1.00%
Margin rate over reference rate (as a percent)							2.50%
Term loan B-2 | Base rate
Long-Term Debt
Floor for reference rate (as a percent)							2.00%
Margin rate over reference rate (as a percent)							1.50%
Notes
Long-Term Debt
Principal amount							$ 650,000	650,000
Net unamortized premium (discount) on Holdco Notes							(10,962)	(13,061)
Total Long-term Debt							639,038	636,939
Face amount of debt											$ 650,000
Interest rate on debt instrument (as a percent)											9.00%
Notes | On or after October 1, 2014
Long-Term Debt
Redemption price as a percentage of principal amount						104.50%
Notes | On or after October 1, 2015
Long-Term Debt
Redemption price as a percentage of principal amount						102.25%
Notes | On and after October 1, 2016 and thereafter
Long-Term Debt
Redemption price as a percentage of principal amount						100.00%
Other
Long-Term Debt
Total Long-term Debt								848
Revolving credit facility
Long-Term Debt
Borrowing capacity	$ 175,000						175,000	$ 200,000
Outstanding balance							0
Letters of credit							4,400
Net availability							$ 170,600
Step down percentage upon achievement of a total senior secured leverage ratio (as a percent)							0.25%
Write off deferred financing cost	359
Financing costs capitalized	$ 611
Unused line fee percentage							0.50%
Fronting fee Percentage							0.25%
Revolving credit facility | Subsequent event
Long-Term Debt
Letters of credit									$ 6,100
Revolving credit facility | Eurodollar (LIBOR)
Long-Term Debt
Margin rate over reference rate (as a percent)							3.25%
Revolving credit facility | Base rate
Long-Term Debt
Margin rate over reference rate (as a percent)							2.25%
Holdco Notes
Long-Term Debt
Face amount of debt										550,000
Holdco Notes | Parent Company
Long-Term Debt
Face amount of debt		$ 450,000								$ 550,000
Cash interest rate (as a percent)										7.75%
PIK interest (as a percent)										8.50%
Cash on hand from Company used to pay transaction fees and expenses and a dividend										$ 200,000
Gross proceeds from issuance of debt		460,125
Premium on issuance of debt		$ 10,125
Holdco Notes | Parent Company | Equal or exceed 75%, but less than 100%
Long-Term Debt
Percentage of outstanding principal amount in which interest is payable by increasing the principal amount of outstanding notes or by issuing PIK Notes equal to such interest							25.00%
Percentage of outstanding principal amount in which interest is payable in cash							75.00%
Holdco Notes | Parent Company | Equal or exceed 50%, but less than 75%
Long-Term Debt
Percentage of outstanding principal amount in which interest is payable in kind							50.00%
Percentage of outstanding principal amount in which interest is payable in cash							50.00%
Holdco Notes | Parent Company | Equal or exceed 25%, but less than 50%
Long-Term Debt
Percentage of outstanding principal amount in which interest is payable in kind							75.00%
Percentage of outstanding principal amount in which interest is payable in cash							25.00%
Holdco Notes | Minimum | Parent Company | Equal or exceed 75%, but less than 100%
Long-Term Debt
Applicable amount for interest period expressed as a percentage of the aggregate amount of cash interest							75.00%
Holdco Notes | Minimum | Parent Company | Equal or exceed 50%, but less than 75%
Long-Term Debt
Applicable amount for interest period expressed as a percentage of the aggregate amount of cash interest							50.00%
Holdco Notes | Minimum | Parent Company | Equal or exceed 25%, but less than 50%
Long-Term Debt
Applicable amount for interest period expressed as a percentage of the aggregate amount of cash interest							25.00%
Holdco Notes | Maximum | Parent Company | Equal or exceed 75%, but less than 100%
Long-Term Debt
Applicable amount for interest period expressed as a percentage of the aggregate amount of cash interest							100.00%
Holdco Notes | Maximum | Parent Company | Equal or exceed 50%, but less than 75%
Long-Term Debt
Applicable amount for interest period expressed as a percentage of the aggregate amount of cash interest							75.00%
Holdco Notes | Maximum | Parent Company | Equal or exceed 25%, but less than 50%
Long-Term Debt
Applicable amount for interest period expressed as a percentage of the aggregate amount of cash interest							50.00%
Holdco Notes | Maximum | Parent Company | Less than 25%
Long-Term Debt
Applicable amount for interest period expressed as a percentage of the aggregate amount of cash interest							25.00%
Holdco Notes | On or after November 1, 2014 | Holdings Shareholders
Long-Term Debt
Redemption price as a percentage of principal amount							102.00%
Holdco Notes | On or after November 1, 2015 | Holdings Shareholders
Long-Term Debt
Redemption price as a percentage of principal amount							101.00%
Holdco Notes | On or after November 1, 2016 and thereafter | Holdings Shareholders
Long-Term Debt
Redemption price as a percentage of principal amount							100.00%
Term loan B-1
Long-Term Debt
Face amount of debt repurchased			1,750,000
Write off deferred financing cost			4,232
Call premium on term loan			1,151
Financing costs capitalized			15,190
Remaining portion of the call premium capitalized			$ 13,924