Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
REVENUES:
Services	$ 570,569	$ 470,756	$ 410,857
Products	240,912	230,876	209,528
Total revenues	811,481	701,632	620,385
COST OF REVENUES:
Cost of services	463,634	382,341	335,118
Cost of products	167,971	160,754	140,956
Total cost of revenues	631,605	543,095	476,074
Gross profit	179,876	158,537	144,311
OPERATING EXPENSES:
Administrative	48,485	41,776	36,133
Salary and payroll taxes	65,619	57,048	53,325
Total operating expenses	114,104	98,824	89,458
Income from operations	65,772	59,713	54,853
OTHER INCOME (EXPENSE), NET:
Interest expense	(6,152)	(2,716)	(3,388)
Other income	823	682	151
Total other income (expense), net	(5,329)	(2,034)	(3,237)
Income before provision for income taxes	60,443	57,679	51,616
PROVISION FOR INCOME TAXES	7,341	6,744	7,293
Net income	$ 53,102	$ 50,935	$ 44,323
INCOME PER SHARE:
Basic (in Dollars per share)	$ 3.57	$ 3.39	$ 2.99
Diluted (in Dollars per share)	$ 3.53	$ 3.35	$ 2.94