Annual report pursuant to Section 13 and 15(d)

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

v3.21.2
ACCUMULATED OTHER COMPREHENSIVE INCOME - Change in AOCI by Component, Net of Tax (Details) - USD ($)
$ in Thousands
 12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance $ 611,433 $ 719,236 $ 868,714
Net current-period OCI 47,853 (12,365) (64,155)
Ending Balance 636,403 611,433 719,236
Total      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance (240,719) (228,361) (164,298)
OCI before reclassification 38,325 (19,891) (64,578)
Amounts reclassified from AOCI 9,655 7,533 515
Net current-period OCI 47,980 (12,358) (64,063)
Ending Balance (192,739) (240,719) (228,361)
Postretirement Benefit Plans      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance (82,954) (71,743) (37,876)
OCI before reclassification 39,822 (18,094) (36,784)
Amounts reclassified from AOCI 7,202 6,883 2,917
Net current-period OCI 47,024 (11,211) (33,867)
Ending Balance (35,930) (82,954) (71,743)
Currency Translation Adjustment      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance (151,881) (156,214) (134,960)
OCI before reclassification (3,370) 4,333 (21,254)
Amounts reclassified from AOCI 0 0 0
Net current-period OCI (3,370) 4,333 (21,254)
Ending Balance (155,251) (151,881) (156,214)
Derivatives      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance (5,884) (404) 8,538
OCI before reclassification 1,873 (6,130) (6,540)
Amounts reclassified from AOCI 2,453 650 (2,402)
Net current-period OCI 4,326 (5,480) (8,942)
Ending Balance (1,558) (5,884) (404)
Noncontrolling Interest      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance 368 375 467
OCI before reclassification (127) (7) (92)
Net current-period OCI (127) (7) (92)
Ending Balance 241 368 375
Postretirement Benefit Plans attributable to Noncontrolling Interest      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance 0 0 0
OCI before reclassification 0 0 0
Net current-period OCI 0 0 0
Ending Balance 0 0 0
Currency Translation Adjustment attributable to Noncontrolling Interest      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance 368 375 467
OCI before reclassification (127) (7) (92)
Net current-period OCI (127) (7) (92)
Ending Balance 241 368 375
Derivatives attributable to Noncontrolling Interest      
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Beginning Balance 0 0 0
OCI before reclassification 0 0 0
Net current-period OCI 0 0 0
Ending Balance $ 0 $ 0 $ 0