Segment Reporting (Segment Reporting Information) (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012 segment		Sep. 30, 2011
Segment Reporting [Abstract]
Reportable segments (in number of segments)					5
Revenues:
Total Revenues	$ 388,283,000		$ 162,370,000		$ 838,046,000		$ 435,491,000
Gross Profit:
Total Gross Profit	119,039,000		54,528,000		263,041,000		146,476,000
Operating Income (Loss):
Total Operating Income	36,496,000		13,736,000		66,097,000		30,930,000
Apex
Segment Reporting Information
Acquisition costs expensed	700,000				9,400,000
Revenues:
Total Revenues	202,664,000		0		301,167,000		0
Gross Profit:
Total Gross Profit	56,934,000		0		83,917,000		0
Operating Income (Loss):
Total Operating Income	16,563,000	[1]	0	[1]	14,594,000	[1]	0	[1]
Oxford
Revenues:
Total Revenues	88,104,000		70,074,000		254,970,000		195,512,000
Gross Profit:
Total Gross Profit	31,250,000		25,113,000		90,266,000		69,483,000
Operating Income (Loss):
Total Operating Income	13,251,000		9,038,000		36,007,000		23,014,000
Life Sciences
Revenues:
Total Revenues	40,646,000		41,820,000		122,506,000		114,403,000
Gross Profit:
Total Gross Profit	14,002,000		14,163,000		41,649,000		39,025,000
Operating Income (Loss):
Total Operating Income	3,020,000		3,026,000		8,291,000		7,378,000
Healthcare
Revenues:
Total Revenues	29,390,000		27,091,000		82,796,000		68,671,000
Gross Profit:
Total Gross Profit	8,483,000		7,458,000		23,622,000		19,242,000
Operating Income (Loss):
Total Operating Income	455,000		(522,000)		936,000		(3,423,000)
Physician
Revenues:
Total Revenues	27,479,000		23,385,000		76,607,000		56,905,000
Gross Profit:
Total Gross Profit	8,370,000		7,794,000		23,587,000		18,726,000
Operating Income (Loss):
Total Operating Income	$ 3,207,000		$ 2,194,000		$ 6,269,000		$ 3,961,000

[1] Three Months Ended Nine Months Ended September 30, September 30, 2012 2011 2012 2011Revenues: Apex$202,664 $— $301,167 $—Oxford88,104 70,074 254,970 195,512Life Sciences40,646 41,820 122,506 114,403Healthcare29,390 27,091 82,796 68,671Physician27,479 23,385 76,607 56,905 $388,283 $162,370 $838,046 $435,491Gross Profit: Apex$56,934 $— $83,917 $—Oxford31,250 25,113 90,266 69,483Life Sciences14,002 14,163 41,649 39,025Healthcare8,483 7,458 23,622 19,242Physician8,370 7,794 23,587 18,726 $119,039 $54,528 $263,041 $146,476Operating Income: Apex (1)$16,563 $— $14,594 $—Oxford13,251 9,038 36,007 23,014Life Sciences3,020 3,026 8,291 7,378Healthcare455 (522) 936 (3,423)Physician3,207 2,194 6,269 3,961 $36,496 $13,736 $66,097 $30,930_____ (1) Apex operating income includes acquisition relate