Long-term incentive compensation	9 Months Ended
Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Long-term incentive compensation	Long-term incentive compensation Long-term incentive program (LTIP) compensation includes both stock-based awards (principally stock-settled stock appreciation rights, restricted stock units, and performance stock units) and long-term performance-based cash awards. Long-term incentive compensation expense, which was primarily general and administrative in nature, was attributed to the Company’s U.S. dialysis and related lab services business, corporate administrative support, and ancillary services and strategic initiatives. The Company’s stock-based compensation awards are measured at their estimated fair values on the date of grant if settled in shares or at their estimated fair values at the end of each reporting period if settled in cash. The value of stock-based awards so measured is recognized as compensation expense on a cumulative straight-line basis over the vesting terms of the awards, adjusted for expected forfeitures. During the nine months ended September 30, 2018, the Company granted 1,897 stock-settled stock appreciation rights with an aggregate grant-date fair value of $30,817 and a weighted-average expected life of approximately 4.2 years and 1,097 restricted and performance stock units with an aggregate grant-date fair value of $72,718 and a weighted-average expected life of approximately 3.3 years. For the nine months ended September 30, 2018 and 2017, the Company recognized $74,077 and $46,972, respectively, in total LTIP expense, of which $60,461 and $25,281, respectively, represented stock-based compensation expense for stock appreciation rights, restricted stock units, performance stock units and discounted employee stock plan purchases, which are primarily included in general and administrative expense. The estimated tax benefits recorded for stock-based compensation for the nine months ended September 30, 2018 and 2017 was $10,887 and $8,497, respectively. During the three months ended September 30, 2018, the Company adopted a retirement policy (Rule of 65 policy). The Rule of 65 policy generally provides that Section 16 executive officers that are a minimum age of 55 with five years of continuous service with the Company receive certain benefits with respect to their outstanding equity awards upon a qualifying retirement if the sum of their age plus years of service is greater than or equal to 65. These benefits generally include accelerated vesting of restricted stock unit awards, continued vesting of stock-settled stock appreciation rights and performance stock unit awards and an exercise window from the original vest date through the original expiration date regardless of continued employment, with pro rata vesting for a Rule of 65 retirement within one year of the award grant date. The adoption of the Rule of 65 policy resulted in a $14,680 modification charge and a net acceleration of expense of $8,790 during the three and nine months ended September 30, 2018 that is included in the expense amounts reported above. As of September 30, 2018, the Company had $122,887 of total estimated but unrecognized compensation expense for outstanding LTIP awards, including $103,923 related to stock-based compensation arrangements under the Company’s equity compensation and employee stock purchase plans. The Company expects to recognize the performance-based cash component of these LTIP costs over a weighted average remaining period of 0.9 year and the stock-based component of these LTIP costs over a weighted average remaining period of 1.5 years. For the nine months ended September 30, 2018 and 2017, the Company recognized $7,919 and $6,046, respectively, in actual tax benefits upon the settlement of stock awards.

Long-term incentive compensation

Long-term incentive program (LTIP) compensation includes both stock-based awards (principally stock-settled stock appreciation rights, restricted stock units, and performance stock units) and long-term performance-based cash awards. Long-term incentive compensation expense, which was primarily general and administrative in nature, was attributed to the Company’s U.S. dialysis and related lab services business, corporate administrative support, and ancillary services and strategic initiatives.

The Company’s stock-based compensation awards are measured at their estimated fair values on the date of grant if settled in shares or at their estimated fair values at the end of each reporting period if settled in cash. The value of stock-based awards so measured is recognized as compensation expense on a cumulative straight-line basis over the vesting terms of the awards, adjusted for expected forfeitures.

During the nine months ended September 30, 2018, the Company granted 1,897 stock-settled stock appreciation rights with an aggregate grant-date fair value of $30,817 and a weighted-average expected life of approximately 4.2 years and 1,097 restricted and performance stock units with an aggregate grant-date fair value of $72,718 and a weighted-average expected life of approximately 3.3 years.

For the nine months ended September 30, 2018 and 2017, the Company recognized $74,077 and $46,972, respectively, in total LTIP expense, of which $60,461 and $25,281, respectively, represented stock-based compensation expense for stock appreciation rights, restricted stock units, performance stock units and discounted employee stock plan purchases, which are primarily included in general and administrative expense. The estimated tax benefits recorded for stock-based compensation for the nine months ended September 30, 2018 and 2017 was $10,887 and $8,497, respectively.

During the three months ended September 30, 2018, the Company adopted a retirement policy (Rule of 65 policy). The Rule of 65 policy generally provides that Section 16 executive officers that are a minimum age of 55 with five years of continuous service with the Company receive certain benefits with respect to their outstanding equity awards upon a qualifying retirement if the sum of their age plus years of service is greater than or equal to 65. These benefits generally include accelerated vesting of restricted stock unit awards, continued vesting of stock-settled stock appreciation rights and performance stock unit awards and an exercise window from the original vest date through the original expiration date regardless of continued employment, with pro rata vesting for a Rule of 65 retirement within one year of the award grant date. The adoption of the Rule of 65 policy resulted in a $14,680 modification charge and a net acceleration of expense of $8,790 during the three and nine months ended September 30, 2018 that is included in the expense amounts reported above.

As of September 30, 2018, the Company had $122,887 of total estimated but unrecognized compensation expense for outstanding LTIP awards, including $103,923 related to stock-based compensation arrangements under the Company’s equity compensation and employee stock purchase plans. The Company expects to recognize the performance-based cash component of these LTIP costs over a weighted average remaining period of 0.9 year and the stock-based component of these LTIP costs over a weighted average remaining period of 1.5 years.

For the nine months ended September 30, 2018 and 2017, the Company recognized $7,919 and $6,046, respectively, in actual tax benefits upon the settlement of stock awards.