Defined Benefit Pension and Other Postretirement Plans (Tables)

3 Months Ended

Dec. 31, 2013

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Component of net periodic pension expense and other postretirement benefit costs

Net periodic pension expense and other postretirement benefit costs relating to our employees include the following components:

	Pension Benefits						Other Postretirement Benefits
	Three Months Ended						Three Months Ended
	December 31,						December 31,
	2013			2012			2013			2012
Service cost	$	1,623		$	2,053		$	41		51
Interest cost	5,721			5,196			127			143
Expected return on assets	(6,650		)	(6,198		)	(139		)	(132		)
Amortization of:
Prior service benefit	—			—			(160		)	(105		)
Actuarial loss	1,748			3,428			37			91
Net benefit cost (income)	2,442			4,479			(94		)	48
Change in associated regulatory liabilities	—			—			918			815
Net expense	$	2,442		$	4,479		$	824		$	863