Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2017

Compensation and Retirement Disclosure [Abstract]

Schedule of Consolidated Net Periodic Benefit Costs

Net periodic benefit expense for the three and six months ended June 30, 2016 and 2017 was as follows (in thousands):



	Three Months Ended						Three Months Ended
	June 30, 2016						June 30, 2017
	Pension Benefits			Other Postretirement Benefits			Pension Benefits			Other Postretirement Benefits
Components of net periodic benefit costs:
Service cost	$	4,405		$	62		$	5,230		$	66
Interest cost⁽¹⁾	1,933			110			2,582			123
Expected return on plan assets⁽¹⁾	(2,331		)	—			(2,646		)	—
Amortization of prior service credit⁽¹⁾	(45		)	(929		)	(46		)	—
Amortization of actuarial loss⁽¹⁾	1,107			185			1,783			200
Settlement cost⁽¹⁾	—			—			361			—
Net periodic benefit cost (credit)	$	5,069		$	(572	)	$	7,264		$	389



	Six Months Ended						Six Months Ended
	June 30, 2016						June 30, 2017
	Pension Benefits			Other Postretirement Benefits			Pension Benefits			Other Postretirement Benefits
Components of net periodic benefit costs:
Service cost	$	9,093		$	123		$	10,248		$	131
Interest cost⁽¹⁾	3,978			220			4,932			245
Expected return on plan assets⁽¹⁾	(4,459		)	—			(5,133		)	—
Amortization of prior service credit⁽¹⁾	(90		)	(1,857		)	(91		)	—
Amortization of actuarial loss⁽¹⁾	2,324			369			2,811			400
Settlement cost⁽¹⁾	—			—			1,726			—
Net periodic benefit cost (credit)	$	10,846		$	(1,145	)	$	14,493		$	776

⁽¹⁾Upon adoption of ASU 2017-07, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, these components of net periodic benefit cost (credit) are reported on the consolidated statements of income as other expense (income). See Note 1 – Organization, Description of Business and Basis of Presentation - New Accounting Pronouncements for further details about this accounting change.

Schedule of Amounts Recognized in Other Comprehensive Loss

The changes in AOCL related to employee benefit plan assets and benefit obligations for the three and six months ended June 30, 2016 and 2017 were as follows (in thousands):



	Three Months Ended						Three Months Ended
	June 30, 2016						June 30, 2017
Gains (Losses) Included in AOCL	Pension Benefits			Other Postretirement Benefits			Pension Benefits			Other Postretirement Benefits
Beginning balance	$	(61,107	)	$	(4,689	)	$	(56,236	)	$	(7,681	)
Amortization of prior service credit	(45		)	(929		)	(46		)	—
Amortization of actuarial loss	1,107			185			1,783			200
Settlement cost	—			—			361			—
Ending balance	$	(60,045	)	$	(5,433	)	$	(54,138	)	$	(7,481	)



	Six Months Ended						Six Months Ended
	June 30, 2016						June 30, 2017
Gains (Losses) Included in AOCL	Pension Benefits			Other Postretirement Benefits			Pension Benefits			Other Postretirement Benefits
Beginning balance	$	(62,279	)	$	(3,945	)	$	(58,584	)	$	(7,881	)
Amortization of prior service credit	(90		)	(1,857		)	(91		)	—
Amortization of actuarial loss	2,324			369			2,811			400
Settlement cost	—			—			1,726			—
Ending balance	$	(60,045	)	$	(5,433	)	$	(54,138	)	$	(7,481	)