EQUITY - Narrative (Details)				1 Months Ended	3 Months Ended		12 Months Ended
	Oct. 15, 2015 USD ($)	Sep. 11, 2015 USD ($) $ / shares	Jul. 08, 2015 shares	Nov. 04, 2015 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) vote $ / shares shares	Sep. 30, 2014 USD ($) $ / shares	Jun. 30, 2015 USD ($) $ / shares shares	Oct. 01, 2015 USD ($)	Aug. 13, 2015 USD ($)
Class of Stock [Line Items]
Share-based compensation					$ (9,500,000)	$ (100,000)
Preferred stock, par value (in dollars per share) | $ / shares					$ 0.01		$ 0.01
Preferred stock, shares authorized | shares					20,000,000.0		20,000,000.0
Preferred stock, shares outstanding | shares					1,900,000.0		1,900,000.0
Authorization to repurchase (up to $700.0)									$ 700,000,000
Dividends declared (in dollars per share) | $ / shares		$ 0.25			$ 0.25	$ 0.20
Minimum
Class of Stock [Line Items]
Share purchase prices | $ / shares					26.91
Minimum | Subsequent Event
Class of Stock [Line Items]
Share purchase prices | $ / shares				$ 25.51
Maximum
Class of Stock [Line Items]
Share purchase prices | $ / shares					$ 30.23
Maximum | Subsequent Event
Class of Stock [Line Items]
Share purchase prices | $ / shares				$ 29.86
Additional Paid-in Capital
Class of Stock [Line Items]
Reclassification of CS from liability to APIC					$ 13,800,000
Additional Paid-in Capital | Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Reduction of dividend accrual recorded in prior period					200,000
Other Noncurrent Liabilities | RSU And Restricted Shares of Class A Common Stock
Class of Stock [Line Items]
Dividends payable								$ 1,100,000
Other Noncurrent Liabilities | Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Dividends payable					$ 2,300,000
Executive Officer | Accrued expenses and other current liabilities
Class of Stock [Line Items]
Recognized compensation expense							$ 13,900,000
Common Class A
Class of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares					$ 0.01		$ 0.01
Number of votes per share | vote					1
Common stock, shares authorized | shares					800,000,000.0		800,000,000.0
Common stock, shares outstanding | shares					94,500,000		98,800,000
Share-based compensation					$ 100,000
Number of shares repurchased | shares					5,500,000
Aggregate fair value of shares repurchased					$ 155,700,000
Common Class A | Subsequent Event
Class of Stock [Line Items]
Number of shares repurchased | shares				11,100,000
Aggregate fair value of shares repurchased				$ 312,200,000
Common Class A | Affiliated Entity
Class of Stock [Line Items]
Related liability | shares			1,400,000
Common Class B
Class of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares					$ 0.01		$ 0.01
Number of votes per share | vote					10
Common stock, shares authorized | shares					262,000,000		262,000,000
Common stock, shares outstanding | shares					262,000,000		262,000,000
Series A Preferred Stock
Class of Stock [Line Items]
Number of votes per share | vote					0
Preferred stock, par value (in dollars per share) | $ / shares					$ 0.01
Conversion price							$ 27.97
Series A Preferred Stock | Additional Paid-in Capital
Class of Stock [Line Items]
Share-based compensation					$ (400,000)
Series A Preferred Stock | Other Noncurrent Liabilities
Class of Stock [Line Items]
Share-based compensation					$ (100,000)
Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized | shares					20,000,000.0
Common Class A and B
Class of Stock [Line Items]
Dividends paid		$ 90,100,000
Common Class A and B | Subsequent Event
Class of Stock [Line Items]
Dividends paid	$ 89,000,000