Pension and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2018

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Schedule of Net Benefit Costs

The net periodic benefit cost for the three and nine months ended September 30, 2018 and 2017 includes the following components: 

	Pension Benefits						Postretirement Benefits
	Three Months Ended   September 30,						Three Months Ended   September 30,
Components of Net Periodic Benefit Cost	2018			2017			2018			2017
Selling, general, and administrative expenses:
Service cost	$	7,134		$	6,604		$	580		$	582
Total selling, general, and administrative expenses	$	7,134		$	6,604		$	580		$	582
Non-operating expenses:
Interest cost	6,830			6,954			659			711
Expected return on plan assets	(7,966		)	(7,658		)	—			—
Amortization of:
Net actuarial loss	6,624			5,376			213			197
Prior service cost (gain)	79			105			(489		)	(545		)
Total non-operating expenses	$	5,567		$	4,777		$	383		$	363
Net periodic benefit cost	$	12,701		$	11,381		$	963		$	945
	Pension Benefits						Postretirement Benefits
	Nine Months Ended   September 30,						Nine Months Ended   September 30,
Components of Net Periodic Benefit Cost	2018			2017			2018			2017
Selling, general, and administrative expenses:
Service cost	$	21,401		$	19,812		$	1,739		$	1,745
Total selling, general, and administrative expenses	$	21,401		$	19,812		$	1,739		$	1,745
Non-operating expenses:
Interest cost	20,491			20,863			1,978			2,133
Expected return on plan assets	(23,897		)	(22,973		)	—			—
Amortization of:
Net actuarial loss	19,871			16,127			639			591
Prior service cost (gain)	238			315			(1,467		)	(1,635		)
Total non-operating expenses	$	16,703		$	14,332		$	1,150		$	1,089
Net periodic benefit cost	$	38,104		$	34,144		$	2,889		$	2,834