Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
PENSION AND OTHER POSTRETIREMENT PLANS - Fair Value Allocation of Plan Assets (Details) - USD ($)
$ in Thousands
Sep. 30, 2018
Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets $ 158,662 $ 155,634
Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 133,762 131,284
Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 14,785 14,870
Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 10,115 9,480
Equity securities - stocks    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 46,628 42,731
Equity securities - stocks | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 46,628 42,731
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 46,117 34,514
Equity securities - mutual funds | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 46,117 34,514
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 41,574 44,902
Fixed income securities | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 26,789 30,032
Fixed income securities | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 14,785 14,870
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 2,676 4,106
Cash and cash equivalents | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 2,676 4,106
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 21,667 29,381
Other investments | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 11,552 19,901
Other investments | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 0
Other investments | Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets $ 10,115 $ 9,480