Note 4 - Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2021

Notes Tables

Schedule of Net Benefit Costs [Table Text Block]

	Three Months Ended June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Service cost	$	1,455		$	1,334		$	2,910		$	2,668
Interest cost		1,248			1,404			2,496			2,808
Expected return on plan assets		(2,313	)		(1,872	)		(4,626	)		(3,744	)
Amortization of prior service cost		99			29			198			58
Amortization of net loss		1,125			1,163			2,250			2,326
Net periodic pension cost	$	1,614		$	2,058		$	3,228		$	4,116