Annual report pursuant to Section 13 and 15(d)

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

v2.4.0.6
Quarterly Financial Information (Summary Of Quarterly Financial Information) (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2010
Sep. 30, 2010
Jun. 30, 2010
Mar. 31, 2010
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Quarterly Financial Information [Abstract]                      
Revenue $ 485,132 $ 494,475 $ 480,255 $ 422,679 $ 398,972 $ 395,981 $ 368,250 $ 317,795 $ 1,882,541 $ 1,480,998 $ 1,245,005
Operating income 63,312 68,194 64,645 37,921 37,969 43,384 40,011 16,375 234,072 137,739 70,391
Net income $ 39,883 $ 38,631 $ 39,383 $ 21,573 $ 22,056 $ 24,381 $ 21,513 $ 7,701 $ 139,470 $ 75,651 $ 34,871
Basic and diluted $ 0.69 $ 0.67 $ 0.69 $ 0.38 $ 0.39 $ 0.44 $ 0.38 $ 0.14 $ 2.44 $ 1.35