Annual report pursuant to Section 13 and 15(d)

ACCUMULATED OTHER COMPREHENSIVE INCOME - Change in AOCI by Component, Net of Tax (Details)

v3.5.0.2
ACCUMULATED OTHER COMPREHENSIVE INCOME - Change in AOCI by Component, Net of Tax (Details) - USD ($)
$ in Thousands
12 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2014
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance $ 734,046 $ 775,206 $ 546,292
Net current-period OCI (31,631) (83,659) (39,762)
Ending Balance 709,334 734,046 775,206
Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance (43,474)    
OCI before reclassification (16,901)    
Amounts reclassified from AOCI 4,325    
Net current-period OCI (12,576)    
Ending Balance (56,050) (43,474)  
Currency Translation Adjustment      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance (104,604)    
OCI before reclassification (17,655)    
Amounts reclassified from AOCI 0    
Net current-period OCI (17,655)    
Ending Balance (122,259) (104,604)  
Derivatives      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance (2,248)    
OCI before reclassification (3,230)    
Amounts reclassified from AOCI 1,919    
Net current-period OCI (1,311)    
Ending Balance (3,559) (2,248)  
Total      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance (150,326) (66,817) (26,940)
OCI before reclassification (37,786)    
Amounts reclassified from AOCI 6,244    
Net current-period OCI (31,542)    
Ending Balance (181,868) (150,326) $ (66,817)
Postretirement Benefit Plans attributable to Noncontrolling Interest      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance 0    
OCI before reclassification 0    
Net current-period OCI 0    
Ending Balance 0 0  
Currency Translation Adjustment attributable to Noncontrolling Interest      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance 366    
OCI before reclassification (89)    
Net current-period OCI (89)    
Ending Balance 277 366  
Derivatives attributable to Noncontrolling Interest      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance 0    
OCI before reclassification 0    
Net current-period OCI 0    
Ending Balance 0 0  
Noncontrolling Interest      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance 366    
OCI before reclassification (89)    
Net current-period OCI (89)    
Ending Balance $ 277 $ 366