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LONG-TERM DEBT (Details) $ in Thousands			1 Months Ended			3 Months Ended		12 Months Ended
LONG-TERM DEBT (Details) $ in Thousands	Jun. 30, 2017 USD ($)	Jul. 31, 2016 AUD ($)	Jul. 31, 2018 GBP (£)	Jul. 31, 2016 AUD ($)	Nov. 30, 2012 CAD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2020 AUD ($) option	Sep. 30, 2020 USD ($) option	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2020 GBP (£)	Sep. 30, 2020 AUD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 CAD ($)	Sep. 29, 2020 AUD ($)	Jun. 22, 2020 USD ($)	Feb. 19, 2020 USD ($)	Jan. 30, 2020 USD ($)	Jan. 29, 2020 USD ($)	Sep. 30, 2019 AUD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2016 USD ($) property	Sep. 30, 2015 USD ($)	Feb. 27, 2014
Debt Instrument [Line Items]
Minimum payments under debt agreements for 2021														$ 9,922,000
Minimum payments under debt agreements for 2022														12,667,000
Minimum payments under debt engagement for 2023														16,124,000
Minimum payments under debt agreements for 2024														1,730,000
Minimum payments under debt agreements for 2025														14,628,000
Minimum payments under debt agreements thereafter														1,009,351,000
Long-term debt, gross														1,064,422,000								$ 1,114,131,000
Capitalized fees & expenses														17,821,000								10,724,000
Gain (loss) from debt extinguishment						$ (969,000)	$ (5,245,000)		$ (7,925,000)	$ 0	$ 0
Line of credit facility, amount outstanding															$ 0
Debt instrument, basis spread on variable rate					1.30%
Outstanding debt														1,046,964,000								1,104,274,000
Revolver Due 2025
Debt Instrument [Line Items]
Line of credit facility, remaining borrowing capacity														370,275,000
Maximum borrowing capacity																			$ 400,000,000	$ 350,000,000
Term Loan \| Northcote Holdings Pty. Ltd
Debt Instrument [Line Items]
Debt instrument, face amount		$ 29,625,000		$ 29,625,000
Line of credit facility, amount outstanding													$ 15,875,000	$ 11,287,000		$ 18,375,000					$ 23,375,000
Debt instrument, periodic payment, principal				1,250,000
Debt instrument, balloon payment		9,625,000		9,625,000
Debt instrument, interest rate at period end												2.09%	2.09%	2.09%	2.09%
Term loan balance increase								$ 5,000,000
Term Loan \| Ames UK
Debt Instrument [Line Items]
Debt instrument, face amount \| £			£ 14,000,000
Debt instrument, periodic payment, principal \| £			438,000
Debt instrument, balloon payment \| £			7,088,000
Revolving Credit Facility \| Northcote Holdings Pty. Ltd
Debt Instrument [Line Items]
Line of credit facility, interest rate at period end												2.04%	2.04%	2.04%	2.04%
Maximum borrowing capacity		20,000,000		20,000,000
Revolving Credit Facility \| Ames UK
Debt Instrument [Line Items]
Debt instrument, face amount \| £			£ 5,000,000
Debt instrument, basis spread on variable rate			1.50%					1.85%	1.85%
Outstanding debt \| £												£ 0
Term and Mortgage Loan July 2018 \| Ames UK
Debt Instrument [Line Items]
Outstanding debt												£ 15,398,000		$ 19,799,000
Letter of Credit Subfacility \| Revolver Due 2025
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity																			100,000,000	50,000,000
Line of credit facility, amount outstanding														$ 16,867,000
Multicurrency Subfacility \| Revolver Due 2025
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity																			100,000,000
Margin Rate \| Revolver Due 2025
Debt Instrument [Line Items]
Line of credit facility, interest rate during period								0.75%	0.75%
LIBOR Rate
Debt Instrument [Line Items]
Line of credit facility, interest rate during period								1.75%	1.75%
Receivables Purchase Facility \| Northcote Holdings Pty. Ltd
Debt Instrument [Line Items]
Debt instrument, face amount		$ 10,000,000		$ 10,000,000
Debt instrument, basis spread on variable rate				1.35%
Outstanding debt													$ 15,000,000								$ 10,000,000
Debt instrument, interest rate at period end												1.49%	1.49%	1.49%	1.49%
Increase in the commitment of receivables purchase line								$ 5,000,000
Finance Lease - Real Estate
Debt Instrument [Line Items]
Long-term debt, gross														$ 17,218,000
Capitalized fees & expenses														30,000
Outstanding debt														17,188,000
Revolver Due 2025
Debt Instrument [Line Items]
Long-term debt, gross														12,858,000
Capitalized fees & expenses														2,209,000
Line of credit facility, current borrowing capacity																			$ 400,000,000	$ 350,000,000
Maximum percentage of equity interest of subsidiaries borrowings guaranteed								65.00%	65.00%
Outstanding debt														10,649,000
Senior Notes \| Fair Value, Inputs, Level 1
Debt Instrument [Line Items]
Notes payable, fair value disclosure														1,040,000,000
Senior Notes \| Senior Notes Due 2028
Debt Instrument [Line Items]
Debt instrument, face amount																	$ 150,000,000	$ 850,000,000
Stated percentage																	5.75%	5.75%
Issuance price, percentage																	100.25%
Capitalized fees & expenses														16,448,000
Unamortized debt issuance expense														$ 15,376,000
Senior Notes \| Senior Notes Due 2022
Debt Instrument [Line Items]
Debt instrument, face amount																	$ 1,000,000,000
Stated percentage												5.25%	5.25%	5.25%	5.25%		5.25%								5.25%
Gain (loss) from debt extinguishment									$ (7,925,000)
Extinguishment of debt, amount									1,000,000,000
Write off of deferred debt issuance cost									6,725,000
Tender offer net premium expense									607,000
Redemption interest expense									$ 593,000
Real Estate Mortgages
Debt Instrument [Line Items]
Debt instrument, face amount																							$ 8,000,000	$ 32,280,000
Number of secured properties \| property																							4
Debt instrument, basis spread on variable rate								1.50%	1.50%
ESOP Loans
Debt Instrument [Line Items]
Debt instrument, periodic payment, principal	$ 569,000								$ 635,000
Outstanding debt														$ 29,878,000
Non U.S. Lines of Credit
Debt Instrument [Line Items]
Long-term debt, gross														0								17,576,000
Capitalized fees & expenses														30,000								45,000
Line of credit facility, remaining borrowing capacity														11,210,000	$ 15,000
Outstanding debt														$ (30,000)								$ 17,531,000
Proceeds from long-term lines of credit					$ 15,000				$ 11,210,000
Non U.S. Lines of Credit \| LIBOR Rate
Debt Instrument [Line Items]
Line of credit facility, interest rate at period end												1.44%	1.44%	1.44%	1.44%
Non U.S. Lines of Credit \| Bankers Acceptance Rate
Debt Instrument [Line Items]
Line of credit facility, interest rate at period end												1.55%	1.55%	1.55%	1.55%
Mortgages \| Ames UK
Debt Instrument [Line Items]
Debt instrument, face amount \| £			£ 4,000,000
Debt instrument, periodic payment, principal \| £			105,000
Debt instrument, balloon payment \| £			£ 2,349,000
London Interbank Offered Rate (LIBOR) \| Term Loan \| Ames UK
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			2.25%					2.30%	2.30%
London Interbank Offered Rate (LIBOR) \| ESOP Loans
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	3.00%							2.91%	2.91%
London Interbank Offered Rate (LIBOR) \| Mortgages \| Ames UK
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			1.80%					1.85%	1.85%
Bank Bill Swap Bid Rate \| Term Loan \| Northcote Holdings Pty. Ltd
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.95%
Bank Bill Swap Bid Rate \| Revolving Credit Facility \| Northcote Holdings Pty. Ltd
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.90%
Troy, Ohio \| Finance Lease - Real Estate
Debt Instrument [Line Items]
Long-term debt, percentage bearing fixed interest, percentage rate												5.00%	5.00%	5.00%	5.00%
Ocala, Florida
Debt Instrument [Line Items]
Finance lease, renewal term												5 years	5 years	5 years	5 years
Ocala, Florida \| Finance Lease - Real Estate
Debt Instrument [Line Items]
Long-term debt, percentage bearing fixed interest, percentage rate												5.60%	5.60%	5.60%	5.60%
Number of option to extend \| option								2	2