Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue	$ 853,297	$ 734,217	$ 2,392,221	$ 2,001,655
Cost of services and products	647,805	563,348	1,824,490	1,546,325
Gross Profit	205,492	170,869	567,731	455,330
Selling, general and administrative expense	51,756	47,056	159,368	145,483
Income from Operations	153,736	123,813	408,363	309,847
Interest income	39	824	472	1,362
Interest expense	(851)	(1,282)	(2,167)	(3,083)
Equity earnings (losses) of unconsolidated affiliates	134	418	109	1,341
Other income (expense), net	(639)	(553)	(840)	(5,212)
Income before Income Taxes	152,419	123,220	405,937	304,255
Provision for income taxes	48,012	38,814	127,870	95,840
Net Income	$ 104,407	$ 84,406	$ 278,067	$ 208,415
Cash Dividends declared per Share	$ 0.22	$ 0.18	$ 0.62	$ 0.51
Basic Earnings per Share	$ 0.97	$ 0.78	$ 2.57	$ 1.93
Diluted Earnings per Share	$ 0.96	$ 0.78	$ 2.56	$ 1.92