Retirement Plans (Tables)

3 Months Ended

Mar. 31, 2019

Defined Benefit Plan Disclosure [Line Items]

Benefit costs

Pension costs, which primarily include costs for the qualified TRP and the non-qualified SERP, are presented in the following table (in thousands):

	Quarter ended Mar. 31,
	2019			2018
Interest cost on benefit obligation	$	5,750		$	5,150
Expected return on plan assets	(6,575		)	(7,450		)
Amortization of prior service cost	25			50
Amortization of actuarial loss	1,500			1,250
Pension payment timing related charge	—			6,300
Expense for company-sponsored retirement plans	$	700		$	5,300