Annual report pursuant to Section 13 and 15(d)

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

v3.20.2
PENSION AND OTHER POSTRETIREMENT PLANS - Fair Value Allocation of Plan Assets (Details) - USD ($)
$ in Thousands
Sep. 30, 2020
Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets $ 168,134 $ 155,313
Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 132,775 125,485
Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 20,086 18,968
Level 3    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 15,273 10,860
Equity securities - stocks    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 37,089 54,985
Equity securities - stocks | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 37,089 54,985
Equity securities - stocks | Level 1 | Class A common stock    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 14,936  
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 81,588 50,312
Equity securities - mutual funds | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 81,588 50,312
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 31,824 34,797
Fixed income securities | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 11,738 15,829
Fixed income securities | Level 2    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 20,086 18,968
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 2,360 4,359
Cash and cash equivalents | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 2,360 4,359
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 15,273 10,860
Other investments | Level 1    
Defined Benefit Plan Disclosure [Line Items]    
Fair value of plan assets 0 0
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 $ 15,273 $ 10,860