Fair Value Measurement	3 Months Ended
Fair Value Measurement	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair value measurement	. Fair Value Measurement Accounting guidance on fair value measurements for certain financial assets and liabilities requires that assets and liabilities carried at fair value be classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable market-based inputs or unobservable inputs that are corroborated by market data. Level 3 — Unobservable inputs reflecting the reporting entity’s own assumptions or external inputs from inactive markets. The classification of a financial asset or liability within the hierarchy is determined based on the lowest level of input that is significant to the fair value measurement. Certain of the Company’s acquisitions contained contingent purchase obligations. The contingent purchase obligation related to acquisitions is measured at fair value on a recurring basis, according to the valuation techniques the Company used to determine fair value. Changes to the fair value are recognized as income or expense within other operating expenses in the condensed consolidated statements of operations. In measuring the fair value of the contingent purchase obligation, the Company used an income approach that considers the expected future earnings of the acquired businesses, for the varying performance periods, based on historical performance and the resulting contingent payments, discounted at a risk-adjusted rate. At March 31, 2017 and December 31, 2016, the Company had no contingent purchase obligations related to acquisitions. At March 31, 2016, the Company had a Level 3 financial liability for a contingent purchase obligation related to an acquisition with a fair value of $4.9 million. There was no change in the fair value of this obligation for the three months ended March 31, 2016.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.