Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Entity-Wide Disclosure (Schedule of Revenues by Geographic Area) (Details)

v3.10.0.1
Entity-Wide Disclosure (Schedule of Revenues by Geographic Area) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Segment Reporting Information [Line Items]      
Revenues $ 663,237 $ 668,362 $ 672,458
Americas (primarily the United States) [Member]      
Segment Reporting Information [Line Items]      
Revenues 409,741 413,326 411,536
Europe and Middle East [Member]      
Segment Reporting Information [Line Items]      
Revenues 147,162 148,279 137,924
Asia Pacific [Member]      
Segment Reporting Information [Line Items]      
Revenues $ 106,334 $ 106,757 $ 122,998