Annual report pursuant to Section 13 and 15(d)

Quarterly Financial Information (Summary of Quarterly Financial Information) (Details)

v3.10.0.1
Quarterly Financial Information (Summary of Quarterly Financial Information) (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Selected Quarterly Financial Information [Abstract]                      
Revenue $ 1,026,944 $ 1,058,233 $ 1,033,498 $ 925,020 $ 891,117 $ 872,987 $ 839,912 $ 754,096 $ 4,043,695 $ 3,358,112 $ 2,991,517
Operating income 218,845 228,385 220,481 149,340 143,457 163,875 160,432 108,122 817,051 575,886 483,835
Net income $ 159,459 $ 173,442 $ 163,434 $ 109,333 $ 197,250 [1] $ 102,314 [1] $ 98,418 [1] $ 65,792 [1] $ 605,668 $ 463,774 [1] $ 295,765
Earnings per share:                      
Earnings Per Share, Basic $ 1.96 $ 2.12 $ 1.99 $ 1.33 $ 2.40 $ 1.24 $ 1.20 $ 0.80 $ 7.39 $ 5.63 $ 3.56
Earnings Per Share, Diluted 1.95 2.12 1.99 1.33 2.39 1.24 1.19 0.80 7.38 5.63 $ 3.56
Dividends declared per share $ 0.13 $ 0.13 $ 0.13 $ 0.13 $ 0.10 $ 0.10 $ 0.10 $ 0.10 $ 0.52 $ 0.40  
[1] During the fourth quarter of 2017, we recorded a provisional tax benefit of $104.9 million due to the remeasurement of our deferred taxes to reflect the impact of the Tax Act