Operating Segments and Geographic Information (Information Related To Reportable Operating Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Total consolidated revenues	$ 243,273	$ 245,888	$ 824,401	$ 848,856
Income (loss) from operations	2,685	(1,215)	47,713	33,633
Foreign currency gain (loss), net	(257)	1,379	181	(1,568)
Interest income	269	178	576	558
Interest expense	(167)	(184)	(539)	(661)
Other income (expense)	54	(1)	187	(108)
Income before income taxes	2,584	157	48,118	31,854
Total consolidated depreciation and amortization	7,886	8,442	24,701	25,473
Reportable Operating Segments [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	243,019	245,617	823,856	848,189
Income (loss) from operations	42,782	35,383	172,324	145,318
Total consolidated depreciation and amortization	2,620	2,772	7,923	9,322
Reportable Operating Segments [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	120,459	114,659	374,336	373,886
Income (loss) from operations	24,102	16,329	71,309	50,919
Total consolidated depreciation and amortization	1,383	1,417	4,075	4,400
Reportable Operating Segments [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	80,039	90,920	303,028	326,268
Income (loss) from operations	13,264	17,303	73,294	77,687
Total consolidated depreciation and amortization	863	1,036	2,710	3,107
Reportable Operating Segments [Member] | Europe [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	42,521	40,038	146,492	148,035
Income (loss) from operations	5,416	1,751	27,721	16,712
Total consolidated depreciation and amortization	374	319	1,138	1,815
Reportable Operating Segments [Member] | Other businesses [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	254	271	545	667
Income (loss) from operations	(6,233)	(7,179)	(16,883)	(19,291)
Total consolidated depreciation and amortization	1,618	1,614	5,106	5,060
Unallocated corporate and other [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	(33,864)	(29,419)	(107,728)	(92,394)
Total consolidated depreciation and amortization	$ 3,648	$ 4,056	$ 11,672	$ 11,091