Selected Balance Sheet And Income Statement Information Selected Income Statement Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue:
Services	$ 1,887,957	$ 1,369,614	$ 1,277,795
Products	894,647	823,049	639,250
Total revenue	2,782,604	2,192,663	1,917,045
Cost of Services and Products:
Services	1,418,511	999,396	916,495
Products	642,199	603,289	461,477
Unallocated expenses	94,036	81,219	72,753
Total cost of services and products	2,154,746	1,683,904	1,450,725
Gross margin:
Services	469,446	370,218	361,300
Products	252,448	219,760	177,773
Unallocated expenses	(94,036)	(81,219)	(72,753)
Gross Margin	$ 627,858	$ 508,759	$ 466,320