Employee Benefits (Tables)

6 Months Ended

Jun. 30, 2020

Retirement Benefits [Abstract]

Net Periodic Benefit Cost

The components of the net periodic benefit cost for our pension and postretirement benefit plans are as follows:

	Pension Plan				Postretirement Benefit Plan
Three Months Ended June 30,	2020		2019		2020		2019
Net periodic benefit cost
Service cost	$	2,707	$	1,997	$	432	$	456
Interest cost	2,066		2,080		253		318
Expected return on plan assets	(3,385)		(2,696)		—		—
Amortization of prior service credit	—		—		(2,021)		(2,221)
Amortization of net loss	979		901		94		224
Net periodic benefit cost	$	2,367	$	2,282	$	(1,242)	$	(1,223)

	Pension Plan				Postretirement Benefit Plan
Six Months Ended June 30,	2020		2019		2020		2019
Net periodic benefit cost
Service cost	$	5,414	$	3,994	$	864	$	912
Interest cost	4,132		4,160		506		637
Expected return on plan assets	(6,770)		(5,392)		—		—
Amortization of prior service credit	—		—		(4,042)		(4,242)
Amortization of net loss	1,958		1,802		188		447
Net periodic benefit cost	$	4,734	$	4,564	$	(2,484)	$	(2,246)