Operating Segments and Geographic Information (Information Related To Reportable Operating Business Segments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Total consolidated revenues	$ 267,907	$ 279,140
Income (loss) from operations	15,582	14,243
Foreign currency gain (loss), net	276	(1,247)
Interest income	150	216
Interest expense	(184)	(243)
Other income	124	82
Income before income taxes	15,948	13,051
Depreciation and amortization	8,446	8,595
Other businesses [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	190	172
Income (loss) from operations	(5,617)	(6,074)
Depreciation and amortization	1,746	1,710
Reportable Operating Segments [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	267,717	278,968
Income (loss) from operations	61,002	48,950
Depreciation and amortization	2,656	3,336
Reportable Operating Segments [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	117,722	124,130
Income (loss) from operations	22,002	16,576
Depreciation and amortization	1,345	1,478
Reportable Operating Segments [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	98,344	104,502
Income (loss) from operations	26,726	25,851
Depreciation and amortization	926	1,078
Reportable Operating Segments [Member] | Europe [Member]
Segment Reporting Information [Line Items]
Total consolidated revenues	51,651	50,336
Income (loss) from operations	12,274	6,523
Depreciation and amortization	385	780
Unallocated corporate and other [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	(39,803)	(28,633)
Depreciation and amortization	$ 4,044	$ 3,549