BASIS OF FINANCIAL STATEMENT PRESENTATION (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled Receivables, Current	$ 72.4us-gaap_UnbilledReceivablesCurrent
Ownership percentage below which investments are generally accounted for on the cost method (in thousandths)	20.00%

This element represents the maximum ownership percentage of cost-method investments held by the Company. Generally, such investments do not have readily determinable fair values and are not required to be accounted for by the equity method. The carrying amount of such securities equates to cost, adjusted for other-than-temporary impairment.

No definition available.

Name:	lh_CostMethodInvestmentsMaximumOwnershipPercentage
Namespace Prefix:	lh_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration