Employee Benefits (Tables)

6 Months Ended

Jun. 30, 2021

Retirement Benefits [Abstract]

Components of 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,	2021		2020		2021		2020
Net periodic benefit cost
Service cost	$	3,020	$	2,707	$	—	$	432
Interest cost	1,728		2,066		1		253
Expected return on plan assets	(4,202)		(3,385)		—		—
Amortization of prior service credit	(809)		—		(3,765)		(2,021)
Amortization of net loss	999		979		705		94
Special event plan closure	—		—		—		—
Net periodic benefit cost	$	736	$	2,367	$	(3,059)	$	(1,242)

	Pension Plan				Postretirement Benefit Plan
Six Months Ended June 30,	2021		2020		2021		2020
Net periodic benefit cost
Service cost	$	6,040	$	5,414	$	148	$	864
Interest cost	3,456		4,132		70		506
Expected return on plan assets	(8,404)		(6,770)		—		—
Amortization of prior service credit	(1,618)		—		(6,962)		(4,042)
Amortization of net loss	1,998		1,958		1,197		188
Special event plan closure	—		—		(20,177)		—
Net periodic benefit cost	$	1,472	$	4,734	$	(25,724)	$	(2,484)