Segment Information (Schedule of Reconciliation of Total Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Segment Assets	$ 2,760,727	$ 2,707,099	$ 2,687,434
Items excluded from segment assets:
Deferred tax assets	280,055	277,887
Operating Segments | Segment assets for total reportable business segments
ASSETS
Segment Assets	1,894,209	1,971,268
Operating Segments | Segment assets for all other business segments
ASSETS
Segment Assets	554,315	508,334
Corporate Reconciling Items And Eliminations
Items excluded from segment assets:
Cash and other investments	234,658	152,432
Deferred tax assets	$ 77,545	$ 75,065