Reconciliation of Benefit Obligations and Plan Assets of U.K. Plan (Details) - UNITED KINGDOM - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Change in benefit obligation:
Projected benefit obligation at beginning of year	$ 39,421	$ 35,193
Interest cost	1,340	1,589
Actuarial (gains) losses	(2,083)	6,060
Benefits paid	(798)	(1,006)
Foreign currency exchange rate changes	(1,966)	(2,415)
Projected benefit obligation at end of year	35,914	39,421
Accumulated benefit obligation at end of year	35,914	39,421
Change in plan assets:
Fair value of plan assets at beginning of year	33,610	33,457
Actual return on plan assets	342	2,234
Employer contributions	955	1,000
Benefits paid	(798)	(1,006)
Foreign currency exchange rate changes	(1,735)	(2,075)
Fair value of plan assets at end of year	32,374	33,610
Funded status at end of year	(3,540)	(5,811)
Amounts included in accumulated other comprehensive loss not yet recognized in net periodic pension cost:
Net actuarial loss	(9,874)	(11,890)
Amounts expected to be amortized from accumulated other comprehensive loss into net periodic pension cost over the next fiscal year consists of:
Net actuarial loss	$ 794	$ 892