Note 8 - Employee Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2018

Notes Tables

Schedule of Net Benefit Costs [Table Text Block]

	Three Months Ended September 30,
	2018			2017
Service cost	$	1,252		$	1,196
Interest cost		1,377			1,339
Expected return on plan assets		(1,634	)		(1,462	)
Amortization of prior service cost		15			(84	)
Amortization of net loss		931			1,033
Net periodic pension cost	$	1,941		$	2,022

	Nine Months Ended September 30,
	2018			2017
Service cost	$	3,756		$	3,588
Interest cost		4,131			4,017
Expected return on plan assets		(4,902	)		(4,386	)
Amortization of prior service cost		45			(252	)
Amortization of net loss		2,793			3,099
Net periodic pension cost	$	5,823		$	6,066