Retirement Plans (Tables)

3 Months Ended

Mar. 31, 2018

Defined Benefit Plan Disclosure

Schedule of Costs of Retirement Plans

The following table summarizes the expense associated with the contributions made to these plans.

	Three Months Ended March 31,
	2018		2017
United States	$	544	$	451
Canada	33		59
United Kingdom	117		115
	$	694	$	625

Pension Plan | United States

Defined Benefit Plan Disclosure

Schedule of Net Benefit Costs

Net periodic pension costs for the United States defined benefit pension plan for the three-month periods ended March 31, 2018 and 2017 are as follows:

	Three Months Ended March 31,
	2018			2017
Interest cost	$	155		$	171
Expected return on plan assets	(213		)	(178		)
Recognized net actuarial loss	24			33
Net periodic pension (income) cost	$	(34	)	$	26

Pension Plan | Foreign Plan

Defined Benefit Plan Disclosure

Schedule of Net Benefit Costs

Net periodic pension costs for the United Kingdom defined benefit pension plan for the three-month periods ended March 31, 2018 and 2017 are as follows:

	Three Months Ended March 31,
	2018			2017
Interest cost	$	53		$	55
Expected return on plan assets	(72		)	(65		)
Amortization of prior service costs and transition amount	5			4
Recognized net actuarial loss	49			69
Net periodic pension cost	$	35		$	63