Organization and Significant Accounting Policies - Business Description (Details) $ / shares in Units, $ in Millions					12 Months Ended
	Nov. 25, 2024 shares	Jul. 26, 2024 USD ($) $ / shares shares	Jun. 25, 2024	Mar. 04, 2024	Dec. 31, 2024 health_center state clinic $ / shares	Nov. 24, 2024
Segment information
Number of occupational health centers operated by entity | health_center					552
Number of onsite health clinics | clinic					157
Number of states in which the entity had operations | state					42
Member interests converted to common shares				1
Stock split conversion ratio			0.233
Common stock, par value (in dollars per share) | $ / shares					$ 0.01
Concentra Group Holdings Parent | Select Medical Corporation
Segment information
Special stock distribution (in shares) | shares	104,093,503
Outstanding membership interest owned by Select						81.70%
IPO
Segment information
Number of shares issued in initial public offering (in shares) | shares		22,500,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.01
Sale of stock, price per share (in dollars per share) | $ / shares		$ 23.50
Consideration received on transaction		$ 499.7
Payments of stock issuance costs		29.1
Net proceeds of IPO and debt financing transactions, excluding amounts repaid for debt		34.7
IPO | Select Medical Revolving Promissory Note
Segment information
Repayments of debt		$ 420.0
Over-Allotment Option
Segment information
Number of shares issued in initial public offering (in shares) | shares		750,000
Consideration received on transaction		$ 16.7
Payments of stock issuance costs		$ 1.0