Annual report pursuant to Section 13 and 15(d)

Quarterly Financial Information (Summary Of Quarterly Financial Information) (Details)

v3.6.0.2
Quarterly Financial Information (Summary Of Quarterly Financial Information) (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Selected Quarterly Financial Information [Abstract]                      
Revenue $ 745,738 $ 782,611 $ 755,435 $ 707,733 $ 734,572 $ 779,474 $ 762,151 $ 696,245 $ 2,991,517 $ 2,972,442 $ 2,787,897
Operating income 113,447 137,404 133,436 99,548 113,922 139,854 140,899 103,565 483,835 498,240 441,307
Net income $ 68,511 $ 85,581 $ 81,388 $ 60,285 $ 72,224 $ 84,368 $ 85,574 $ 62,524 $ 295,765 $ 304,690 $ 267,514
Earnings Per Share, Basic $ 0.83 $ 1.03 $ 0.98 $ 0.72 $ 0.85 $ 0.99 $ 1.00 $ 0.73 $ 3.56 $ 3.57 $ 3.10
Earnings Per Share, Diluted $ 0.83 $ 1.03 $ 0.98 $ 0.72 $ 0.85 $ 0.99 $ 1.00 $ 0.73 $ 3.56 $ 3.57 $ 3.10