Pension Plans (Tables)

9 Months Ended

Sep. 30, 2018

Retirement Benefits [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 September 30,						For the Nine Months Ended September 30,
	2018			2017			2018			2017
	(In thousands)
Service cost	$	8,124		$	8,445		$	24,839		$	25,215
Interest cost	1,199			1,009			3,668			3,029
Expected return on plan assets	(1,390		)	(1,124		)	(4,249		)	(3,385		)
Amortization of prior service cost	—			—			—			31
Recognized actuarial (gain) loss	(36		)	18			(113		)	62
Net periodic pension cost	$	7,897		$	8,348		$	24,145		$	24,952

Summary of defined contribution expense

The following table summarizes our defined contribution expense:

	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2018		2017		2018		2017
	(In thousands)
Defined contribution expense	$	2,595	$	2,230	$	9,608	$	8,009