Annual report pursuant to Section 13 and 15(d)

PENSION AND OTHER POSTRETIREMENT PLANS - Fair Value Allocation of Plan Assets (Details)

v3.8.0.1
PENSION AND OTHER POSTRETIREMENT PLANS - Fair Value Allocation of Plan Assets (Details) - USD ($)
$ in Thousands
Sep. 30, 2017
Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets $ 155,634 $ 151,864
Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 131,284 127,306
Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 14,870 11,742
Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 9,480 12,816
Equity securities - stocks    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 42,731 35,912
Equity securities - stocks | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 42,731 35,912
Equity securities - stocks | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 0
Equity securities - stocks | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 0
Equity securities - mutual funds    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 34,514 22,937
Equity securities - mutual funds | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 34,514 22,937
Equity securities - mutual funds | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 0
Equity securities - mutual funds | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 0
Fixed income securities    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 44,902 52,831
Fixed income securities | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 30,032 41,099
Fixed income securities | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 14,870 11,732
Fixed income securities | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 0
Cash and cash equivalents    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 4,106 19,664
Cash and cash equivalents | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 4,106 19,664
Cash and cash equivalents | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 0
Cash and cash equivalents | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 0
Other investments    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 29,381 20,520
Other investments | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 19,901 7,694
Other investments | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 10
Other investments | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets $ 9,480 $ 12,816