BASIS OF PRESENTATION, CONSOLIDATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Foreign Currency Exposure (Details)	Sep. 30, 2017	Sep. 30, 2016
One British pound sterling into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.34	1.30
One British pound sterling into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.34	1.30
One euro into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.18	1.12
One euro into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.18	1.12
One Australian dollar into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.78	0.77
One Australian dollar into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.78	0.77
One Norwegian kroner into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.1256	0.1251
One Norwegian kroner into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.1256	0.1251
One Nigerian naira into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.0028	0.0032
One Nigerian naira into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.0028	0.0032
High | One British pound sterling into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.36	1.34
High | One British pound sterling into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.36	1.48
High | One euro into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.20	1.13
High | One euro into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.20	1.15
High | One Australian dollar into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.81	0.77
High | One Australian dollar into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.81	0.78
High | One Norwegian kroner into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.1294	0.1251
High | One Norwegian kroner into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.1294	0.1251
High | One Nigerian naira into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.0032	0.0036
High | One Nigerian naira into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.0033	0.0050
Average | One British pound sterling into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.31	1.31
Average | One British pound sterling into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.29	1.37
Average | One euro into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.17	1.12
Average | One euro into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.14	1.12
Average | One Australian dollar into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.79	0.76
Average | One Australian dollar into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.77	0.75
Average | One Norwegian kroner into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.1257	0.1201
Average | One Norwegian kroner into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.1216	0.1206
Average | One Nigerian naira into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.0029	0.0032
Average | One Nigerian naira into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.0031	0.0040
Low | One British pound sterling into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.28	1.29
Low | One British pound sterling into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.24	1.29
Low | One euro into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.13	1.10
Low | One euro into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	1.06	1.10
Low | One Australian dollar into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.76	0.74
Low | One Australian dollar into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.74	0.72
Low | One Norwegian kroner into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.1190	0.1163
Low | One Norwegian kroner into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.1152	0.1163
Low | One Nigerian naira into U.S. dollars | Quarter To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.0027	0.0029
Low | One Nigerian naira into U.S. dollars | Year To Date
Schedule of Foreign Currency [Line Items]
Foreign currency exchange rates	0.0027	0.0029