Retirement Plans (Tables)

9 Months Ended

Sep. 30, 2017

Defined Benefit Plan Disclosure [Line Items]

Schedule of Costs of Retirement Plans

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

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
United States	$	415	$	152	$	1,276	$	1,289
Canada	53		46		167		164
United Kingdom	93		64		306		281
	$	561	$	262	$	1,749	$	1,734

United States Plan

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs

Net periodic pension costs for the United States defined benefit pension plans for the three- and nine-month periods ended September 30, 2017 and 2016 are as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2017			2016			2017			2016
Service cost	$	—		$	9		$	—		$	27
Interest cost	171			186			513			559
Expected return on plan assets	(178		)	(179		)	(533		)	(538		)
Recognized net actuarial loss	33			69			98			207
Net periodic pension cost	$	26		$	85		$	78		$	255

United Kingdom Benefit Plans

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs

Net periodic pension costs for the United Kingdom defined benefit pension plan for the three- and nine-month periods ended September 30, 2017 and 2016 are as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2017			2016			2017			2016
Interest cost	$	56		$	73		$	168		$	223
Expected return on plan assets	(67		)	(82		)	(201		)	(250		)
Amortization of prior service costs and transition amount	4			5			12			15
Recognized net actuarial loss	72			38			216			116
Net periodic pension cost	$	65		$	34		$	195		$	104