Noncontrolling Interests Subject to Put Provisions and Other Commitments	12 Months Ended
Dec. 31, 2017
Accounting Policies [Abstract]
Noncontrolling Interests Subject to Put Provisions and Other Commitments	Noncontrolling interests subject to put provisions and other commitments Noncontrolling interests subject to put provisions The Company has potential obligations to purchase the equity interests held by third parties in several of its majority-owned joint ventures and other nonconsolidated entities. These obligations are in the form of put provisions that are exercisable at the third-party owners’ discretion within specified periods as outlined in each specific put provision. If these put provisions were exercised, the Company would be required to purchase the third-party owners’ equity interests at either the appraised fair market value or a predetermined multiple of earnings or cash flows attributable to the equity interests put to the Company, which is intended to approximate fair value. The methodology the Company uses to estimate the fair values of noncontrolling interests subject to put provisions assumes the higher of either a liquidation value of net assets or an average multiple of earnings, based on historical earnings, patient mix and other performance indicators that can affect future results, as well as other factors. The estimated fair values of noncontrolling interests subject to put provisions are a critical accounting estimate that involves significant judgments and assumptions and may not be indicative of the actual values at which the noncontrolling interests may ultimately be settled, which could vary significantly from the Company’s current estimates. The estimated fair values of noncontrolling interests subject to put provisions can fluctuate and the implicit multiple of earnings at which these noncontrolling interests obligations may be settled will vary significantly depending upon market conditions including potential purchasers’ access to the capital markets, which can impact the level of competition for dialysis and non-dialysis related businesses, the economic performance of these businesses and the restricted marketability of the third-party owners’ equity interests. The amount of noncontrolling interests subject to put provisions that employ a contractually predetermined multiple of earnings rather than fair value are immaterial. The Company has certain other potential commitments to provide operating capital to a number of dialysis centers that are wholly-owned by third parties or businesses in which the Company owns a noncontrolling equity interest as well as to physician-owned vascular access clinics or medical practices that the Company operates under management and administrative service agreements of approximately $5,385. Certain consolidated joint ventures are originally contractually scheduled to dissolve after terms ranging from 10 to 50 years. While noncontrolling interests in these limited life entities qualify as mandatorily redeemable financial instruments, they are subject to a classification and measurement scope exception from the accounting guidance generally applicable to other mandatorily redeemable financial instruments. Future distributions upon dissolution of these entities would be valued below the related noncontrolling interest carrying balances in the consolidated balance sheet. Other commitments In January 2017, the Company entered into a Sourcing and Supply Agreement with Amgen USA Inc. (Amgen) that expires on December 31, 2022, replacing the Company’s prior agreement that was to expire in 2018. Under the terms of the agreement, the Company will purchase EPO in amounts necessary to meet no less than 90% of its requirements for erythropoiesis-stimulating agents (ESAs) through the expiration of the contract from Amgen. The actual amount of EPO that the Company will purchase will depend upon the amount of EPO administered during dialysis as prescribed by physicians and the overall number of patients that the Company serves. In 2010, the Company entered into an agreement with Fresenius Medical Care (FMC) which committed the Company to purchase a certain amount of dialysis equipment, parts and supplies from FMC through 2013. This agreement has been subsequently extended through December 31, 2020. During 2017, 2016 and 2015, the Company purchased $176,212, $164,766 and $154,566, respectively, of certain equipment, parts and supplies from FMC. In 2014, the Company entered into an agreement with Baxter Healthcare (Baxter) which committed the Company to purchase a certain amount of its hemodialysis non-equipment product supplies, such as dialyzers, at fixed prices through 2018. During 2017, 2016 and 2015, the Company purchased $166,764, $162,109 and $112,931 of hemodialysis product supplies from Baxter under this agreement. Other than operating leases disclosed in Note 14 to the consolidated financial statements, the letters of credit disclosed in Note 13 to the consolidated financial statements, and the arrangements as described above, the Company has no off balance sheet financing arrangements as of December 31, 2017.

Noncontrolling interests subject to put provisions and other commitments

Noncontrolling interests subject to put provisions

The Company has potential obligations to purchase the equity interests held by third parties in several of its majority-owned joint ventures and other nonconsolidated entities. These obligations are in the form of put provisions that are exercisable at the third-party owners’ discretion within specified periods as outlined in each specific put provision. If these put provisions were exercised, the Company would be required to purchase the third-party owners’ equity interests at either the appraised fair market value or a predetermined multiple of earnings or cash flows attributable to the equity interests put to the Company, which is intended to approximate fair value. The methodology the Company uses to estimate the fair values of noncontrolling interests subject to put provisions assumes the higher of either a liquidation value of net assets or an average multiple of earnings, based on historical earnings, patient mix and other performance indicators that can affect future results, as well as other factors. The estimated fair values of noncontrolling interests subject to put provisions are a critical accounting estimate that involves significant judgments and assumptions and may not be indicative of the actual values at which the noncontrolling interests may ultimately be settled, which could vary significantly from the Company’s current estimates. The estimated fair values of noncontrolling interests subject to put provisions can fluctuate and the implicit multiple of earnings at which these noncontrolling interests obligations may be settled will vary significantly depending upon market conditions including potential purchasers’ access to the capital markets, which can impact the level of competition for dialysis and non-dialysis related businesses, the economic performance of these businesses and the restricted marketability of the third-party owners’ equity interests. The amount of noncontrolling interests subject to put provisions that employ a contractually predetermined multiple of earnings rather than fair value are immaterial.

The Company has certain other potential commitments to provide operating capital to a number of dialysis centers that are wholly-owned by third parties or businesses in which the Company owns a noncontrolling equity interest as well as to physician-owned vascular access clinics or medical practices that the Company operates under management and administrative service agreements of approximately $5,385.

Certain consolidated joint ventures are originally contractually scheduled to dissolve after terms ranging from 10 to 50 years. While noncontrolling interests in these limited life entities qualify as mandatorily redeemable financial instruments, they are subject to a classification and measurement scope exception from the accounting guidance generally applicable to other mandatorily redeemable financial instruments. Future distributions upon dissolution of these entities would be valued below the related noncontrolling interest carrying balances in the consolidated balance sheet.

Other commitments

In January 2017, the Company entered into a Sourcing and Supply Agreement with Amgen USA Inc. (Amgen) that expires on December 31, 2022, replacing the Company’s prior agreement that was to expire in 2018. Under the terms of the agreement, the Company will purchase EPO in amounts necessary to meet no less than 90% of its requirements for erythropoiesis-stimulating agents (ESAs) through the expiration of the contract from Amgen. The actual amount of EPO that the Company will purchase will depend upon the amount of EPO administered during dialysis as prescribed by physicians and the overall number of patients that the Company serves.

In 2010, the Company entered into an agreement with Fresenius Medical Care (FMC) which committed the Company to purchase a certain amount of dialysis equipment, parts and supplies from FMC through 2013. This agreement has been subsequently extended through December 31, 2020. During 2017, 2016 and 2015, the Company purchased $176,212, $164,766 and $154,566, respectively, of certain equipment, parts and supplies from FMC.

In 2014, the Company entered into an agreement with Baxter Healthcare (Baxter) which committed the Company to purchase a certain amount of its hemodialysis non-equipment product supplies, such as dialyzers, at fixed prices through 2018. During 2017, 2016 and 2015, the Company purchased $166,764, $162,109 and $112,931 of hemodialysis product supplies from Baxter under this agreement.

Other than operating leases disclosed in Note 14 to the consolidated financial statements, the letters of credit disclosed in Note 13 to the consolidated financial statements, and the arrangements as described above, the Company has no off balance sheet financing arrangements as of December 31, 2017.