EARNINGS PER SHARE (EPS) (Details) - Summary of Reconciliation of Share Amounts Used in Earnings Per Share - USD ($)			3 Months Ended		6 Months Ended
	Jan. 17, 2017	Jul. 14, 2016	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average shares outstanding - basic			41,477,000	41,277,000	41,700,000	40,307,000
Incremental shares from stock based compensation			1,288,000	1,557,000	1,362,000	1,740,000
Convertible debt matured 2017			0	395,000	0	729,000
Weighted average shares outstanding - diluted			42,765,000	43,229,000	43,062,000	42,776,000
Senior notes due 2022 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt conversion, original debt, amount		$ 125,000,000
Convertible Notes 2017 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt conversion, converted instrument, amount	$ 173,855,000			$ 173,855,000
Debt conversion, converted instrument, cash received	$ 125,000,000			$ 125,000,000
Debt conversion, converted instrument, shares issued	1,954,993			1,954,993