Fair value measurements	3 Months Ended
Fair value measurements	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements At March 31, 2016, the Company had no debt outstanding under the Credit Facility, and $10.5 million of outstanding letters of credit. Substantially all of the debt incurs interest at a variable interest rate and, therefore, the carrying amount approximates fair value. The fair value of the debt is classified as a Level 2 measurement because interest rates charged are similar to other financial instruments with similar terms and maturities. The fair value of the Company’s Senior Notes is estimated using Level 2 inputs in the fair value hierarchy and is based on quoted prices for those or similar instruments. At March 31, 2016, the fair value and the carrying value of the Company’s Senior Notes approximated $346.0 million and $402.3 million, respectively. At December 31, 2015, the fair value and the carrying value of the Company’s Senior Notes approximated $334.1 million and $402.5 million, respectively. There were no outstanding financial assets as of March 31, 2016 and December 31, 2015 that required measuring the amounts at fair value. The Company did not change its valuation techniques associated with recurring fair value measurements from prior periods and there were no transfers between levels of the fair value hierarchy during 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.