Pension and Other Postretirement Benefit Costs (Tables)

6 Months Ended

Jun. 30, 2018

Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]

Schedule of Net Benefit Costs

The following table provides the components of net periodic benefit cost for our pension and other postretirement benefit plans:

	Three Months Ended June 30,												Six Months Ended June 30,
	Pension Benefits						Other Postretirement Benefits						Pension Benefits						Other Postretirement Benefits
In thousands	2018			2017			2018			2017			2018			2017			2018			2017
Service cost	$	1,807		$	1,870		$	79		$	99		$	3,614		$	3,740		$	159		$	197
Interest cost	4,183			4,472			241			274			8,366			8,944			482			548
Expected return on plan assets	(5,150		)	(5,112		)	—			—			(10,301		)	(10,225		)	—			—
Amortization of prior service costs	10			31			(117		)	(117		)	21			63			(234		)	(234		)
Amortization of net actuarial loss	4,524			3,622			112			139			9,047			7,243			222			277
Net periodic benefit cost	5,374			4,883			315			395			10,747			9,765			629			788
Amount allocated to construction	(685		)	(1,558		)	(28		)	(135		)	(1,367		)	(3,079		)	(55		)	(267		)
Amount deferred to regulatory balancing account(1)	(2,747		)	(1,508		)	—			—			(5,503		)	(3,035		)	—			—
Net amount charged to expense	$	1,942		$	1,817		$	287		$	260		$	3,877		$	3,651		$	574		$	521

⁽¹⁾ The deferral of defined benefit pension plan expenses above or below the amount set in rates was approved by the OPUC, with recovery of these deferred amounts through the implementation of a balancing account. The balancing account includes the expectation of higher net periodic benefit costs than costs recovered in rates in the near-term with lower net periodic benefit costs than costs recovered in rates expected in future years. Deferred pension expense balances include accrued interest at the utility’s authorized rate of return, with the equity portion of the interest recognized when amounts are collected in rates. See Note 2 in the 2017 Form 10-K.

Schedule of Amounts Recognized in Other Comprehensive Income (Loss)

The following table presents amounts recognized in accumulated other comprehensive loss (AOCL) and the changes in AOCL related to our non-qualified employee benefit plans:

	Three Months Ended June 30,						Six Months Ended June 30,
In thousands	2018			2017			2018			2017
Beginning balance	$	(8,284	)	$	(6,815	)	$	(8,438	)	$	(6,951	)
Amounts reclassified from AOCL:
Amortization of actuarial losses	209			225			418			450
Total reclassifications before tax	209			225			418			450
Tax (benefit) expense	(56		)	(88		)	(111		)	(177		)
Total reclassifications for the period	153			137			307			273
Ending balance	$	(8,131	)	$	(6,678	)	$	(8,131	)	$	(6,678	)