Employee Benefits (Tables)

9 Months Ended

Sep. 30, 2018

Retirement Plans

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs

The net periodic benefit cost recognized for the three, nine and twelve months endedSeptember 30, 2018 and 2017, is made up of the components listed below as determined using the projected unit credit actuarial cost method (in thousands):

	Three Months Ended						Nine Months Ended						Twelve Months Ended
	September 30,						September 30,						September 30,
	2018			2017			2018			2017			2018			2017
Components of net periodic benefit cost:
Service cost	$	2,801		$	2,129		$	8,316		$	6,388		$	10,446		$	8,388
Interest cost	3,214			3,264			9,659			9,794			12,924			13,053
Expected return on plan assets	(5,176		)	(4,797		)	(15,806		)	(14,392		)	(20,603		)	(19,112		)
Amortization of:
Net loss	2,214			2,114			6,414			6,341			8,527			8,175
Prior service benefit	(875		)	(877		)	(2,630		)	(2,630		)	(3,506		)	(3,506		)
Net periodic benefit cost	$	2,178		$	1,833		$	5,953		$	5,501		$	7,788		$	6,998

Other Postretirement Benefit Plans

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs

The net periodic benefit recognized for the three, nine and twelve months endedSeptember 30, 2018 and 2017, is made up of the components listed below (in thousands):

	Three Months Ended						Nine Months Ended						Twelve Months Ended
	September 30,						September 30,						September 30,
	2018			2017			2018			2017			2018			2017
Components of net periodic benefit:
Service cost	$	696		$	559		$	2,096		$	1,677		$	2,655		$	2,267
Interest cost	559			680			1,689			2,042			2,370			2,593
Expected return on plan assets	(602		)	(477		)	(1,827		)	(1,430		)	(2,304		)	(1,893		)
Amortization of:
Prior service benefit	(1,538		)	(1,537		)	(4,613		)	(4,613		)	(6,151		)	(6,151		)
Net gain	(574		)	(419		)	(1,624		)	(1,258		)	(2,044		)	(1,659		)
Net periodic benefit	$	(1,459	)	$	(1,194	)	$	(4,279	)	$	(3,582	)	$	(5,474	)	$	(4,843	)