SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Y	Dec. 31, 2012	Dec. 31, 2011
Accounting Policies [Abstract]
Number of primary laboratories (in number of laboratories)	44
Minimum number of patient service centers (in number of service centers)	1,700
Minimum number of employees (in number of employees)	34,000
Minimum number of patient specimens processed daily (in number of patient specimens)	490,000
Number of Canadian provinces where the Company provides clinical laboratory testing services (in number of provinces)	3
Ownership percentage below which investments are generally accounted for on the cost method (in hundredths)	20.00%
Revenue from Medicare and Medicaid programs, percentage (in hundredths)	16.00%	17.60%	19.00%
Revenue from capitated agreements with certain managed care customers, percentage (in hundredths)	3.20%	3.00%	2.90%
Cash balances on deposit that exceed the balances insured by the F.D.I.C.	$ 52.8
Cash equivalents	367.5
Accounts receivable balances (gross) from Medicare and Medicaid	128.6		121.1
Estimated useful life of capitalized software costs (in years)	5
Minimum threshold percentage required to recognize income tax benefit (in hundredths)	50.00%
Accounts receivable from Ontario government sponsored healthcare plan	$ 33.2	$ 26.7
Percent of gross accounts receivable due from patients	27.80%	28.30%