Accumulated Other Comprehensive Income (Tables)

9 Months Ended

Jun. 30, 2019

Equity [Abstract]

Schedule of Changes in Accumulated Other Comprehensive Income

The tables below present changes in AOCI, net of tax, during the three and nine months ended June 30, 2019 and 2018:

Three Months Ended June 30, 2019	Postretirement Benefit Plans			Derivative Instruments			Total
AOCI — March 31, 2019	$	(6,367	)	$	(19,728	)	$	(26,095	)
Net losses on interest rate contract	—			(1,197		)	(1,197		)
Reclassifications of benefit plan actuarial losses and net prior service benefits	132			—			132
Reclassifications of net losses on IRPAs	—			620			620
AOCI — June 30, 2019	$	(6,235	)	$	(20,305	)	$	(26,540	)
Three Months Ended June 30, 2018	Postretirement Benefit Plans			Derivative Instruments			Total
AOCI — March 31, 2018	$	(8,555	)	$	(16,612	)	$	(25,167	)
Reclassifications of benefit plan actuarial losses and net prior service benefits	220			—			220
Reclassifications of net losses on IRPAs	—			592			592
AOCI — June 30, 2018	$	(8,335	)	$	(16,020	)	$	(24,355	)

Nine Months Ended June 30, 2019	Postretirement Benefit Plans			Derivative Instruments			Total
AOCI — September 30, 2018	$	(4,920	)	$	(15,409	)	$	(20,329	)
Net losses on interest rate contract	—			(3,016		)	(3,016		)
Reclassifications of benefit plan actuarial losses and net prior service benefits	397			—			397
Reclassifications of net losses on IRPAs	—			1,859			1,859
Reclassification of stranded income tax effects related to TCJA	(1,712		)	(3,739		)	(5,451		)
AOCI — June 30, 2019	$	(6,235	)	$	(20,305	)	$	(26,540	)
Nine Months Ended June 30, 2018	Postretirement Benefit Plans			Derivative Instruments			Total
AOCI — September 30, 2017	$	(8,995	)	$	(17,796	)	$	(26,791	)
Reclassifications of benefit plan actuarial losses and net prior service benefits	660			—			660
Reclassifications of net losses on IRPAs	—			1,776			1,776
AOCI — June 30, 2018	$	(8,335	)	$	(16,020	)	$	(24,355	)