Reconciliation of Benefit Obligations and Plan Assets of U.K. Plan (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in benefit obligation:
Projected benefit obligation at beginning of year		$ 36,882	$ 40,329
Interest cost		971	939	$ 991
Actuarial (gains) losses		3,005	(1,718)
Benefits paid		(1,696)	(1,301)
Prior service cost	[1]		754
Foreign currency exchange rate changes		1,294	(2,121)
Projected benefit obligation at end of year		40,456	36,882	40,329
Accumulated benefit obligation at end of year		40,456	36,882
Change in plan assets:
Fair value of plan assets at beginning of year		33,124	36,476
Actual return on plan assets		5,410	(1,083)
Employer contributions		894	941
Benefits paid		(1,696)	(1,301)
Foreign currency exchange rate changes		1,251	(1,909)
Fair value of plan assets at end of year		38,983	33,124	36,476
Funded status at end of year		(1,473)	(3,758)
Amounts included in accumulated other comprehensive loss not yet recognized in net periodic pension cost:
Net actuarial losses at beginning of year		(11,120)	(10,493)
Net actuarial gains (losses) during the year		734	(1,083)
Prior service cost arising during the year	[1]		(754)
Amounts reclassified from accumulated other comprehensive income to income before income taxes		986	826
Foreign currency exchange rate changes		(306)	384
Net actuarial losses		(9,706)	(11,120)	$ (10,493)
Amounts expected to be amortized from accumulated other comprehensive loss into net periodic pension cost over the next fiscal year consists of:
Net actuarial losses		706	959
Prior service cost		$ 30	$ 29

[1] On October 26, 2018, the High Court of Justice in the U.K. ruled that the Guaranteed Minimum Pensions (“GMPs”) provided by pension schemes need to equalize lifetime GMP benefits between genders. In order to meet the requirements set out by the High Court, the Company recorded an estimate of $0.8 million additional benefit obligations based on the existing plan participants, the date the U.K. Plan was allowed to stop accruing additional benefits, the pension plan rules and the approach taken to equalize the benefits. The additional benefit obligations will be amortized and recognized as part of net periodic pension cost in the consolidated statement of operations over the average remaining life expectancy of the plan participants.