Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue	$ 3,287,019	$ 2,782,604	$ 2,192,663
Cost of services and products	2,521,483	2,154,746	1,683,904
Gross Margin	765,536	627,858	508,759
Selling, general and administrative expense	220,420	199,261	173,928
Income from Operations	545,116	428,597	334,831
Interest income	554	1,935	888
Interest expense, net of amounts capitalized	(2,194)	(4,218)	(1,096)
Equity earnings of unconsolidated affiliates	133	1,673	3,801
Other income (expense), net	(1,273)	(6,065)	(539)
Income before Income Taxes	542,336	421,922	337,885
Provision for income taxes	170,836	132,905	102,227
Net Income	$ 371,500	$ 289,017	$ 235,658
Cash Dividends declared per Share	$ 0.84	$ 0.69	$ 0.45
Basic Earnings per Share	$ 3.43	$ 2.68	$ 2.18
Weighted Average Number of Shares Outstanding, Basic	108,158	108,015	108,308
Diluted Earnings per Share	$ 3.42	$ 2.66	$ 2.16
Weighted Average Number of Shares Outstanding, Diluted	108,731	108,617	109,001