Pension Plans (Tables)

6 Months Ended

Jun. 30, 2017

Compensation and Retirement Disclosure [Abstract]

Components of net periodic pension cost

The components of net periodic pension cost for these defined benefit pension plans are as follows:

	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2017			2016			2017			2016
	(In thousands)
Service cost	$	8,430		$	8,490		$	16,770		$	16,660
Interest cost	1,013			924			2,020			1,828
Expected return on plan assets	(1,133		)	(956		)	(2,261		)	(1,903		)
Amortization of prior service cost	—			8			31			17
Recognized actuarial loss	22			23			44			47
Net periodic pension cost	$	8,332		$	8,489		$	16,604		$	16,649

Defined contribution plan disclosures

The following table summarizes our defined contribution expense:

	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2017		2016		2017		2016
	(In thousands)
Defined contribution expense	$	2,581	$	2,231	$	5,779	$	5,166