Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2016

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Periodic Benefit Costs of Pension and Post-Retirement Healthcare

Components of the net periodic benefit cost related to the Company's qualified pension plans and other post-employment benefit plans for the three and six months ended June 30, 2016 and 2015 are as follows (in thousands):

	Three Months Ended June 30, 2016						Three Months Ended June 30, 2015
	Qualified Pension Plans			Post- employment Benefit Plans			Qualified Pension Plans			Post- employment Benefit Plans
Service cost	$	1,593		$	41		$	1,823		$	62
Interest cost	3,821			1,008			3,633			1,013
Expected return on plan assets	(3,834		)	—			(3,658		)	—
Amortization of actuarial loss	1,349			31,704			1,886			32,838
Amortization of prior service cost	(761		)	(88,259		)	(863		)	(89,550		)
Plan settlement	—			—			607			—
Net periodic benefit cost	2,168			(55,506		)	3,428			(55,637		)
Less capitalized portion	(148		)	—			(251		)	—
Other post-employment benefit and pension expense	$	2,020		$	(55,506	)	$	3,177		$	(55,637	)

	Six Months Ended June 30, 2016						Six Months Ended June 30, 2015
	Qualified Pension Plans			Post- employment Benefit Plans			Qualified Pension Plans			Post- employment Benefit Plans
Service cost	$	3,185		$	82		$	5,169		$	4,417
Interest cost	7,641			2,016			7,444			5,678
Expected return on plan assets	(7,668		)	—			(7,223		)	—
Amortization of actuarial loss	2,698			63,407			3,741			47,874
Amortization of prior service cost	(1,521		)	(176,275		)	(1,207		)	(125,526		)
Plan settlement	—			—			607			—
Net periodic benefit cost	4,335			(110,770		)	8,531			(67,557		)
Less capitalized portion	(279		)	—			(332		)	—
Other post-employment benefit and pension expense	$	4,056		$	(110,770	)	$	8,199		$	(67,557	)