Annual report pursuant to Section 13 and 15(d)

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

v2.4.1.9
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, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Selected Quarterly Financial Information [Abstract]                      
Revenue $ 721,048us-gaap_SalesRevenueServicesNet $ 743,586us-gaap_SalesRevenueServicesNet $ 702,987us-gaap_SalesRevenueServicesNet $ 620,276us-gaap_SalesRevenueServicesNet $ 592,470us-gaap_SalesRevenueServicesNet $ 616,458us-gaap_SalesRevenueServicesNet $ 590,304us-gaap_SalesRevenueServicesNet $ 538,416us-gaap_SalesRevenueServicesNet $ 2,787,897us-gaap_SalesRevenueServicesNet $ 2,337,648us-gaap_SalesRevenueServicesNet $ 2,134,579us-gaap_SalesRevenueServicesNet
Operating income 112,298us-gaap_OperatingIncomeLoss 126,262us-gaap_OperatingIncomeLoss 122,695us-gaap_OperatingIncomeLoss 80,052us-gaap_OperatingIncomeLoss 76,845us-gaap_OperatingIncomeLoss 98,076us-gaap_OperatingIncomeLoss 97,573us-gaap_OperatingIncomeLoss 65,944us-gaap_OperatingIncomeLoss 441,307us-gaap_OperatingIncomeLoss 338,438us-gaap_OperatingIncomeLoss 285,254us-gaap_OperatingIncomeLoss
Net income $ 69,869us-gaap_NetIncomeLoss $ 77,909us-gaap_NetIncomeLoss $ 73,849us-gaap_NetIncomeLoss $ 45,887us-gaap_NetIncomeLoss $ 47,156us-gaap_NetIncomeLoss $ 60,149us-gaap_NetIncomeLoss $ 58,255us-gaap_NetIncomeLoss $ 40,553us-gaap_NetIncomeLoss $ 267,514us-gaap_NetIncomeLoss $ 206,113us-gaap_NetIncomeLoss $ 169,452us-gaap_NetIncomeLoss
Basic and diluted $ 0.81us-gaap_EarningsPerShareBasicAndDiluted $ 0.90us-gaap_EarningsPerShareBasicAndDiluted $ 0.86us-gaap_EarningsPerShareBasicAndDiluted $ 0.53us-gaap_EarningsPerShareBasicAndDiluted $ 0.55us-gaap_EarningsPerShareBasicAndDiluted $ 0.70us-gaap_EarningsPerShareBasicAndDiluted $ 0.68us-gaap_EarningsPerShareBasicAndDiluted $ 0.47us-gaap_EarningsPerShareBasicAndDiluted $ 3.10us-gaap_EarningsPerShareBasicAndDiluted $ 2.39us-gaap_EarningsPerShareBasicAndDiluted