Employee Benefits (Tables)

9 Months Ended

Sep. 30, 2017

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, 2017 and 2016 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,
	2017			2016			2017			2016			2017			2016
Components of net periodic benefit cost:
Service cost	$	2,129		$	2,191		$	6,388		$	6,001		$	8,388		$	8,199
Interest cost	3,264			3,250			9,794			9,780			13,053			13,403
Expected return on plan assets	(4,797		)	(4,734		)	(14,392		)	(14,159		)	(19,112		)	(19,108		)
Amortization of:
Net loss	2,114			1,730			6,341			5,505			8,175			8,167
Prior service benefit	(877		)	(875		)	(2,630		)	(2,630		)	(3,506		)	(3,506		)
Net periodic benefit cost	$	1,833		$	1,562		$	5,501		$	4,497		$	6,998		$	7,155

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, 2017 and 2016 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,
	2017			2016			2017			2016			2017			2016
Components of net periodic benefit:
Service cost	$	559		$	749		$	1,677		$	2,179		$	2,267		$	3,042
Interest cost	680			871			2,042			2,616			2,593			3,625
Expected return on plan assets	(477		)	(452		)	(1,430		)	(1,372		)	(1,893		)	(1,889		)
Amortization of:
Prior service benefit	(1,537		)	(788		)	(4,613		)	(2,363		)	(6,151		)	(3,130		)
Net gain	(419		)	(643		)	(1,258		)	(1,973		)	(1,659		)	(2,479		)
Net periodic benefit	$	(1,194	)	$	(263	)	$	(3,582	)	$	(913	)	$	(4,843	)	$	(831	)