SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Schedule of Revenue by Major Customers) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Revenue, Major Customer [Line Items]
Revenues from significant customers	$ 188,677	$ 227,797	$ 296,351	$ 307,819	$ 363,176	$ 330,562	$ 350,387	$ 351,726	$ 1,020,644	$ 1,395,851	$ 1,173,953
Shell Offshore Inc. [Member]
Revenue, Major Customer [Line Items]
Revenues from significant customers									213,785	201,190	179,763
Kosmos Energy [Member]
Revenue, Major Customer [Line Items]
Revenues from significant customers									184,475	142,701	12,933
Noble Energy Inc. [Member]
Revenue, Major Customer [Line Items]
Revenues from significant customers									179,545	227,682	169,851
Chevron Australia Pty. Ltd. [Member]
Revenue, Major Customer [Line Items]
Revenues from significant customers									118,471	156,099	175,334
Woodside Energy Ltd. [Member]
Revenue, Major Customer [Line Items]
Revenues from significant customers									109,236	166,796	68,484
Apache Energy Ltd. [Member]
Revenue, Major Customer [Line Items]
Revenues from significant customers									$ 0	$ 39,233	$ 209,871