Employee Benefits (Tables)

6 Months Ended

Jun. 30, 2018

Retirement Plans

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs

The net periodic benefit cost recognized for the three, six and twelve months endedJune 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						Six Months Ended						Twelve Months Ended
	June 30,						June 30,						June 30,
	2018			2017			2018			2017			2018			2017
Components of net periodic benefit cost:
Service cost	$	2,757		$	1,989		$	5,515		$	4,259		$	9,774		$	8,450
Interest cost	3,222			3,282			6,445			6,530			12,974			13,039
Expected return on plan assets	(5,315		)	(4,787		)	(10,630		)	(9,595		)	(20,224		)	(19,049		)
Amortization of:
Net loss	2,100			2,138			4,200			4,227			8,427			7,791
Prior service benefit	(877		)	(875		)	(1,755		)	(1,753		)	(3,508		)	(3,504		)
Net periodic benefit cost	$	1,887		$	1,747		$	3,775		$	3,668		$	7,443		$	6,727

Other Postretirement Benefit Plans

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs

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

	Three Months Ended						Six Months Ended						Twelve Months Ended
	June 30,						June 30,						June 30,
	2018			2017			2018			2017			2018			2017
Components of net periodic benefit:
Service cost	$	700		$	530		$	1,400		$	1,118		$	2,518		$	2,457
Interest cost	565			684			1,130			1,362			2,491			2,784
Expected return on plan assets	(612		)	(483		)	(1,225		)	(953		)	(2,179		)	(1,868		)
Amortization of:
Prior service benefit	(1,537		)	(1,538		)	(3,075		)	(3,076		)	(6,150		)	(5,402		)
Net gain	(525		)	(444		)	(1,050		)	(839		)	(1,889		)	(1,883		)
Net periodic benefit	$	(1,409	)	$	(1,251	)	$	(2,820	)	$	(2,388	)	$	(5,209	)	$	(3,912	)