Long-term incentive compensation	6 Months Ended
Jun. 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) as well as 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 six months ended June 30, 2018, the Company granted 1,780 stock-settled stock appreciation rights with an aggregate grant-date fair value of $28,630 and a weighted-average expected life of approximately 4.2 years and 1,094 stock units with an aggregate grant-date fair value of $72,469 and a weighted-average expected life of approximately 3.4 years. For the six months ended June 30, 2018 and 2017, the Company recognized $31,301 and $27,183, respectively, in total LTIP expense, of which $20,717 and $16,404, respectively, represented stock-based compensation expense for stock appreciation rights, restricted 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 six months ended June 30, 2018 and 2017 was $3,941 and $5,636, respectively. As of June 30, 2018, the Company had $153,984 of total estimated but unrecognized compensation expense for outstanding LTIP awards, including $128,115 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 1.0 year and the stock-based component of these LTIP costs over a weighted average remaining period of 1.7 years. For the six months ended June 30, 2018 and 2017, the Company recognized $7,671 and $5,693, respectively, in actual tax benefits upon the exercise 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) as well as 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 six months ended June 30, 2018, the Company granted 1,780 stock-settled stock appreciation rights with an aggregate grant-date fair value of $28,630 and a weighted-average expected life of approximately 4.2 years and 1,094 stock units with an aggregate grant-date fair value of $72,469 and a weighted-average expected life of approximately 3.4 years.

For the six months ended June 30, 2018 and 2017, the Company recognized $31,301 and $27,183, respectively, in total LTIP expense, of which $20,717 and $16,404, respectively, represented stock-based compensation expense for stock appreciation rights, restricted 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 six months ended June 30, 2018 and 2017 was $3,941 and $5,636, respectively.

As of June 30, 2018, the Company had $153,984 of total estimated but unrecognized compensation expense for outstanding LTIP awards, including $128,115 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 1.0 year and the stock-based component of these LTIP costs over a weighted average remaining period of 1.7 years.

For the six months ended June 30, 2018 and 2017, the Company recognized $7,671 and $5,693, respectively, in actual tax benefits upon the exercise of stock awards.