Long-Term Debt and Notes Payable - Principal Maturities Of Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Long-term debt and notes payable
2018	$ 19,013
2019	15,011
2020	42,826
2021	734,406
2022	1,412,899
Thereafter	1,332,585
Total	3,556,740	$ 2,744,080
Select Excluding Concentra
Long-term debt and notes payable
2018	17,843
2019	14,707
2020	36,785
2021	721,721
2022	256,500
Thereafter	1,089,212
Total	2,136,768	2,118,252
Select Excluding Concentra | Credit facility | Revolving facility
Long-term debt and notes payable
2018	0
2019	0
2020	0
2021	0
2022	245,000
Thereafter	0
Total	245,000	230,000
Select Excluding Concentra | Credit facility | Term loan
Long-term debt and notes payable
2018	8,625
2019	11,500
2020	11,500
2021	11,500
2022	11,500
Thereafter	1,083,875
Total	$ 1,138,500	$ 1,141,375
Select Excluding Concentra | Senior notes | 6.375% Senior Notes Due June 2021
Long-term debt and notes payable
Interest rate of debt (as a percent)	6.375%	6.375%
2018	$ 0
2019	0
2020	0
2021	710,000
2022	0
Thereafter	0
Total	710,000	$ 710,000
Select Excluding Concentra | Other
Long-term debt and notes payable
2018	9,218
2019	3,207
2020	25,285
2021	221
2022	0
Thereafter	5,337
Total	43,268	36,877
Concentra Inc
Long-term debt and notes payable
2018	1,170
2019	304
2020	6,041
2021	12,685
2022	1,156,399
Thereafter	243,373
Total	1,419,972	625,828
Concentra Inc | Credit facility | Term loan
Long-term debt and notes payable
2018	0
2019	0
2020	5,719
2021	12,365
2022	1,156,091
Thereafter	240,000
Total	1,414,175	619,175
Concentra Inc | Other
Long-term debt and notes payable
2018	1,170
2019	304
2020	322
2021	320
2022	308
Thereafter	3,373
Total	$ 5,797	$ 6,653