LONG-TERM DEBT - Credit Facilities (Details) - USD ($)		1 Months Ended			12 Months Ended
	Aug. 11, 2015	Nov. 30, 2015	Jul. 31, 2015	Nov. 30, 2013	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014	Jul. 31, 2012
Debt Instrument [Line Items]
Accrued interest					$ 5,512,000	$ 12,055,000
Credit Facility | Senior Secured Credit Facilities
Debt Instrument [Line Items]
Loan face amount				$ 955,000,000.0
Accrued interest payable, including commitment fees					179,000	195,000
Credit Facility | Senior Secured Credit Facilities | Term Loan A Facility | LIBOR
Debt Instrument [Line Items]
Variable rate, measurement period				1 month
Credit Facility | Senior Secured Credit Facility - Revolving
Debt Instrument [Line Items]
Loan face amount				$ 100,000,000
Proceeds from credit facility					560,000,000	442,000,000	$ 310,000,000
Debt outstanding					13,000,000
Letters of credit issued					2,500,000
Credit facility outstanding					0
Remaining borrowing capacity					84,500,000
Prepayments on credit facility					$ 568,000,000	458,000,000	273,000,000
Credit Facility | Senior Secured Credit Facility - Revolving | Minimum
Debt Instrument [Line Items]
Fee assessed on unused revolving credit (as a percent)				0.375%
Credit Facility | Senior Secured Credit Facility - Revolving | Maximum
Debt Instrument [Line Items]
Fee assessed on unused revolving credit (as a percent)				0.50%
Credit Facility | Senior Secured Credit Facility - Revolving | LIBOR | Minimum
Debt Instrument [Line Items]
Variable rate, leverage based margin (as a percent)				2.50%
Credit Facility | Senior Secured Credit Facility - Revolving | LIBOR | Maximum
Debt Instrument [Line Items]
Variable rate, leverage based margin (as a percent)				3.50%
Credit Facility | Senior Secured Credit Facility - Revolving | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)					3.00%
Debt instrument, variable rate at period end (as a percent)					3.50%
Credit Facility | Senior Secured Credit Facility - Revolving | Eurodollar | Minimum
Debt Instrument [Line Items]
Variable rate, leverage based margin (as a percent)				3.50%
Credit Facility | Senior Secured Credit Facility - Revolving | Eurodollar | Maximum
Debt Instrument [Line Items]
Variable rate, leverage based margin (as a percent)				4.50%
Credit Facility | Senior Secured Credit Facility - Revolving | One-Month London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				1.00%
Credit Facility | Senior Secured Credit Facility - Revolving | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				0.50%
Credit Facility | Senior Secured Credit Facility - Revolving | Revolving Credit Facility
Debt Instrument [Line Items]
Fee assessed on unused revolving credit (as a percent)					0.375%
Credit Facility | Senior Secured Credit Facility - Term Loan A
Debt Instrument [Line Items]
Loan face amount				$ 125,000,000
Proceeds from credit facility					$ 0	0	124,343,000
Interest rate, year one (as a percent)				5.00%
Interest rate, year two (as a percent)				7.50%
Interest rate, year three (as a percent)				10.00%
Debt outstanding					$ 96,900,000
Effective interest rate of amounts outstanding (as a percent)					5.47%
Prepayments on credit facility					$ 14,001,000	7,756,000	3,125,000
Credit Facility | Senior Secured Credit Facility - Term Loan A | LIBOR | Minimum
Debt Instrument [Line Items]
Variable rate, leverage based margin (as a percent)				2.50%
Credit Facility | Senior Secured Credit Facility - Term Loan A | LIBOR | Maximum
Debt Instrument [Line Items]
Variable rate, leverage based margin (as a percent)				3.50%
Credit Facility | Senior Secured Credit Facility - Term Loan A | Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)					4.00%
Debt instrument, variable rate at period end (as a percent)					0.52%
Credit Facility | Senior Secured Credit Facility - Term Loan A | Eurodollar | Minimum
Debt Instrument [Line Items]
Variable rate, leverage based margin (as a percent)				3.50%
Credit Facility | Senior Secured Credit Facility - Term Loan A | Eurodollar | Maximum
Debt Instrument [Line Items]
Variable rate, leverage based margin (as a percent)				4.50%
Credit Facility | Senior Secured Credit Facility - Term Loan A | One-Month London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				1.00%
Credit Facility | Senior Secured Credit Facility - Term Loan A | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				0.50%
Credit Facility | Senior Secured Credit Facility - Term Loan B
Debt Instrument [Line Items]
Loan face amount				$ 730,000,000
Proceeds from credit facility	$ 90,000,000				$ 0	87,911,000	720,952,000
Amortization of principal, percentage, annual (as a percent)				1.00%
Debt outstanding					$ 776,100,000
Effective interest rate of amounts outstanding (as a percent)					6.38%
Prepayments on credit facility					$ 30,456,000	5,339,000	5,475,000
Credit Facility | Senior Secured Credit Facility - Term Loan B | LIBOR
Debt Instrument [Line Items]
Variable rate, minimum (as a percent)				1.00%
Credit Facility | Senior Secured Credit Facility - Term Loan B | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				3.50%
Variable rate, minimum (as a percent)				2.00%
Credit Facility | Senior Secured Credit Facility - Term Loan B | Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				4.50%	4.50%
Debt instrument, variable rate at period end (as a percent)					1.00%
Credit Facility | Bank of America, N.A. Line of Credit
Debt Instrument [Line Items]
Proceeds from credit facility					$ 459,701,000	446,935,000	356,796,000
Borrowing capacity				$ 16,500,000.0
Prepayments on credit facility					459,701,000	449,976,000	353,755,000
Accrued interest					14,000	23,000
Credit Facility | Downs Lodging Credit Facility
Debt Instrument [Line Items]
Prepayments on credit facility					40,516,000	0	0
Credit Facility | Downs Lodging Credit Facility | Downs Lodging, LLC
Debt Instrument [Line Items]
Loan face amount								$ 45,000,000.0
Credit facility outstanding		$ 40,500,000
Note stated interest rate (as a percent)								13.00%
Prepayments on credit facility			$ 4,500,000
Credit Facility | New Downs Lodging Credit Facility
Debt Instrument [Line Items]
Proceeds from credit facility					25,000,000	0	0
Prepayments on credit facility					3,344,000	0	$ 0
Credit Facility | New Downs Lodging Credit Facility | Downs Lodging, LLC
Debt Instrument [Line Items]
Loan face amount		$ 25,000,000.0
Credit facility outstanding					$ 21,700,000
Effective interest rate of amounts outstanding (as a percent)					6.19%
Accrued interest					$ 73,000	$ 5,300,000
Debt covenant, maximum total debt subject to earlier maturity (as a percent)		5.00%
Amortization of principal		$ 260,000
Credit Facility | New Downs Lodging Credit Facility | Eurodollar | Downs Lodging, LLC
Debt Instrument [Line Items]
Debt instrument, variable rate at period end (as a percent)					0.56%