SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Mar. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation	The interim unaudited consolidated financial statements reflect all adjustments which in the opinion of management are necessary for a fair statement of results of operations, comprehensive income, financial condition, cash flows and stockholders' equity for the periods presented. Except as otherwise disclosed, all such adjustments are of a normal recurring nature. Operating results for the interim periods are not necessarily indicative of the results that may be expected for the full year. These interim unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements included in the Company’s 2015 Annual Report on Form 10-K. The year-end balance sheet data was derived from the audited financial statements as of December 31, 2015, but does not include all the disclosures required by accounting principles generally accepted in the United States (“GAAP”).
Reclassifications	Prior to the Company's clinical trials central laboratory services joint venture, Q² Solutions, the earnings of the Company's equity method investees consisted of earnings that were not directly taxable to the investees, in which case it was appropriate to present equity in earnings of equity method investees before income tax expense on the consolidated statements of operations. The earnings of Q² Solutions, which closed on July 1, 2015, includes earnings that are directly taxable to the joint venture. As a result of the Q² Solutions transaction, the current period presentation of equity in earnings of equity method investees is required to be presented below income tax expense on the consolidated statements of operations. The Company's equity in earnings of equity method investees on the consolidated statements of operations for the three months ended March 31, 2015 has been reclassified to conform with the current period presentation.
Use Of Estimates	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Earnings Per Share	The Company's unvested restricted stock units that contain non-forfeitable rights to dividends are participating securities and, therefore, are included in the earnings allocation in computing earnings per share using the two-class method. Basic earnings per common share is calculated by dividing net income, adjusted for earnings allocated to participating securities, by the weighted average number of common shares outstanding. Diluted earnings per common share is calculated by dividing net income, adjusted for earnings allocated to participating securities, by the weighted average number of common shares outstanding after giving effect to all potentially dilutive common shares outstanding during the period. Potentially dilutive common shares include the dilutive effect of outstanding stock options and performance share units granted under the Company's Amended and Restated Employee Long-Term Incentive Plan and its Amended and Restated Non-Employee Director Long-Term Incentive Plan. Earnings allocable to participating securities include the portion of dividends declared as well as the portion of undistributed earnings during the period allocable to participating securities.
Property, Plant and Equipment	In connection with the Company’s annual review of the estimated useful lives of its property, plant and equipment completed during the first quarter of 2016, the Company revised the estimated useful lives of certain classes of its property, plant and equipment. In order to better reflect the Company's current expectations regarding the use of its assets, the recent operational improvements from its Invigorate program and considering historical and other data, the Company revised the estimated useful lives of its laboratory equipment from a range of five to seven years to a range of seven to ten years, furniture and fixtures from a range of three to seven years to a range of five to twelve years and computer software obtained for internal use from three years to five years. The change in estimated useful lives was accounted for prospectively as a change in accounting estimate effective in the first quarter of 2016. The impact of this change during the first quarter of 2016 was a decrease in depreciation expense and an increase in operating income of $10 million and an increase in net income of $6 million, or $0.04 per share on a basic and diluted basis. The full year impact for 2016 is expected to be a decrease in depreciation expense and an increase in operating income of $36 million and an increase in net income of $22 million, or $0.16 per share on a basic and diluted basis.
New Accounting Pronouncements	In May 2014, the Financial Accounting Standards Board ("FASB") issued an accounting standard update ("ASU") on revenue recognition. This ASU outlines a single comprehensive model to use in accounting for revenue arising from contracts with customers. This standard supersedes existing revenue recognition requirements and eliminates most industry-specific guidance from GAAP. The core principle of the revenue recognition standard is to require an entity to recognize as revenue the amount that reflects the consideration to which it expects to be entitled in exchange for goods or services as it transfers control to its customers. The standard requires additional disclosures including those that are qualitative and quantitative disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. In August 2015, the FASB deferred the effective date of this ASU to the first quarter of 2018, with early adoption permitted beginning in the first quarter of 2017. The ASU can be applied using a full retrospective method or a modified retrospective method of adoption. The Company is currently assessing the impact of the adoption of this ASU on the Company’s results of operations, financial position and cash flows. On January 1, 2016, the Company adopted a new accounting standard issued by the FASB which makes targeted amendments to the current consolidation guidance for variable interest entities and limited partnerships and similar entities. The adoption of this standard did not have a material impact on the Company's results of operations, financial position and cash flows. On January 1, 2016, the Company prospectively adopted a new accounting standard issued by the FASB which provides guidance in determining whether a cloud computing arrangement includes a software license. If it is determined that a cloud computing arrangement does include a software license, the software element of the arrangement should be accounted for consistent with the acquisition of other software licenses. If the arrangement does not include a software license, it should be accounted for as a service contract. The adoption of this standard did not have a material impact on the Company's results of operations, financial position and cash flows. On January 1, 2016, the Company prospectively adopted a new accounting standard issued by the FASB which requires that an acquirer recognize adjustments to provisional amounts in a business combination that are identified during the measurement period in the reporting period in which the adjustment amounts are determined, including the cumulative effect of the change in provisional amount as if the accounting had been completed at the acquisition date. The adoption of this standard did not have a material impact on the Company's results of operations, financial position and cash flows. During the first quarter of 2016, the Company prospectively adopted a new accounting standard issued by the FASB that clarifies that a change in the counterparty to a derivative instrument that has been designated as a hedging instrument does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The adoption of this standard did not have a material impact on the Company's results of operations, financial position and cash flows. In January 2016, the FASB issued an ASU on the recognition and measurement of financial assets and financial liabilities. This ASU requires that all equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) be measured at fair value with changes in fair value recognized in net income. However, companies may elect to measure equity investments that do not have readily determinable fair values at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. In addition, the ASU eliminates the requirement to disclose the method and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet. The ASU is effective for the Company in the first quarter of 2018. The Company does not expect the adoption of this ASU to have a material impact on its results of operations, financial position and cash flows. In February 2016, the FASB issued an ASU that amends accounting for leases. Under the new guidance, a lessee will recognize assets and liabilities for most leases on its balance sheet but will recognize expense on its statement of operations similar to current lease accounting. The ASU is effective for the Company in the first quarter of 2019 with early adoption permitted. The new guidance must be adopted using a modified retrospective transition approach, and provides for certain practical expedients. The adoption of this ASU will result in a significant increase to the Company’s balance sheet for lease liabilities and right-of-use assets, which has not yet been quantified. The Company is currently evaluating this and the other effects of adoption of this ASU on its consolidated financial statements. In March 2016, the FASB issued an ASU that simplifies the transition to the equity method of accounting by requiring adoption as of the date the investment becomes qualified for equity method accounting. Therefore, upon qualifying for the equity method of accounting as a result of an increase in the level of ownership interest or degree of influence, no retroactive adjustment of the investment is required. The ASU is effective for the Company in the first quarter of 2017 with early adoption permitted. The Company does not expect the adoption of this ASU to have a material impact on its results of operations, financial position and cash flows. In March 2016, the FASB issued an ASU that simplifies several aspects of the accounting for share-based payment award transactions, including the income tax consequences, classification of awards as either equity or liabilities, classification on the statement of cash flows and accounting for forfeitures. The ASU is effective for the Company in the first quarter of 2017 with early adoption permitted. The Company is currently evaluating the guidance to determine the Company's adoption method and the effect it will have on its results of operations, financial position and cash flows.
Derivative Financial Instruments	The Company uses derivative financial instruments to manage its exposure to market risks for changes in interest rates and, from time to time, foreign currencies. This strategy includes the use of interest rate swap agreements, forward starting interest rate swap agreements, treasury lock agreements and foreign currency forward contracts to manage its exposure to movements in interest and currency rates. The Company has established policies and procedures for risk assessment and the approval, reporting and monitoring of derivative financial instrument activities. These policies prohibit holding or issuing derivative financial instruments for speculative purposes. The Company does not enter into derivative financial instruments that contain credit-risk-related contingent features or requirements to post collateral.
Interest Rate Risk	The Company is exposed to interest rate risk on its cash and cash equivalents and its debt obligations. Interest income earned on cash and cash equivalents may fluctuate as interest rates change; however, due to their relatively short maturities, the Company does not hedge these assets or their investment cash flows and the impact of interest rate risk is not material. The Company's debt obligations consist of fixed-rate and variable-rate debt instruments. The Company's primary objective is to achieve the lowest overall cost of funding while managing the variability in cash outflows within an acceptable range. In order to achieve this objective, the Company has entered into interest rate swaps. Interest rate swaps involve the periodic exchange of payments without the exchange of underlying principal or notional amounts. Net settlements between the counterparties are recognized as an adjustment to interest expense, net.