Employee Benefit Plans - Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Change in Benefit Obligation:
Benefit obligation at beginning of period	$ 91,514	$ 82,320
Additional obligation due to acquisition	5,317
Service cost	82	8
Interest cost	2,319	2,288
Actuarial loss	(5,643)	1,021
Plan amendments	2,490
Benefits paid	(1,436)	(1,797)
Foreign-exchange rate changes	(5,113)	7,674
Benefit obligation at end of year	89,530	91,514
Change in Plan Assets:
Fair value of plan assets at beginning of period	64,886	52,538
Additional obligation due to acquisition	2,189
Actual return on plan assets	(1,434)	6,579
Employer contributions	2,477	2,297
Benefits paid	(1,415)	(1,782)
Foreign-exchange rate changes	(3,734)	5,254
Fair value of plan assets at end of period	63,777	64,886
Funded status at end of year			$ (26,561)	$ (26,628)
Net amount recognized in the Consolidated Balance Sheets:
Accrued compensation and benefits (a)			(1,811)	(1,551)
Pension liability (b)			(25,269)	(25,496)
Minimum regulatory benefit for Philippine legal entity			500
Amounts recognized in accumulated other comprehensive loss, net of tax consist of:
Net actuarial loss	(9,301)	(11,054)
Net amount recognized in accumulated other comprehensive loss			9,301	11,054
Plans with underfunded or non-funded accumulated benefit obligation:
Aggregate fair value of plan assets	64,886	52,538	63,777	64,886
Overfunded Plan [Member]
Change in Plan Assets:
Fair value of plan assets at end of period	62,969
Plans with underfunded or non-funded accumulated benefit obligation:
Aggregate fair value of plan assets	62,969		62,969
Underfunded Plan [Member]
Change in Plan Assets:
Fair value of plan assets at beginning of period	64,886
Fair value of plan assets at end of period		64,886
Plans with underfunded or non-funded accumulated benefit obligation:
Aggregate fair value of plan assets	64,886	64,886		64,886
Underfunded Or Unfunded Plan [Member]
Change in Plan Assets:
Fair value of plan assets at beginning of period	64,886
Fair value of plan assets at end of period	62,969	64,886
Plans with underfunded or non-funded accumulated benefit obligation:
Aggregate projected benefit obligation			89,530	91,514
Aggregate accumulated benefit obligation			89,530	91,514
Aggregate fair value of plan assets	$ 64,886	$ 64,886	62,969	64,886
U.K. And Asterion Plans
Net amount recognized in the Consolidated Balance Sheets:
Pension liability (b)			(24,750)	$ (25,077)
Germany And Norway Pension Plans
Net amount recognized in the Consolidated Balance Sheets:
Pension liability (b)			$ (2,300)