Commitments and Contingencies (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) lawsuit facility policy	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) lawsuit facility center policy	Sep. 30, 2016 USD ($)	Oct. 31, 2014 facility
Malpractice Insurance [Line Items]
Number of professional liability lawsuits | lawsuit	71		71
Cash expenditures for self-insured professional liability costs			$ 6,077,000	$ 2,779,000
Other Insurance
Liability for workers compensation claims	$ 871,000		871,000
Workers compensation insurance, non current receivable for excess premiums paid	1,652,000		1,652,000
Hurricane Harvey and Irma
Hurricane costs	$ 232,000	$ 0	$ 232,000	$ 0
Unfavorable regulatory action | Potential violations of false claims act
Malpractice Insurance [Line Items]
Number of facilities | facility	6		6		2
Professional malpractice liability insurance
Malpractice Insurance [Line Items]
Liability for reported and estimated future claims	$ 19,592,000		$ 19,592,000
Prefunded deductible policy
Malpractice Insurance [Line Items]
Insurance policy coverage limits per claim			500,000
Other Insurance
Insurance policy coverage limits per claim			500,000
Professional liability insurance, annual coverage limit per facility			3,000,000
Health insurance, maximum self-insured annual amount per individual	175,000		175,000
Liability for reported claims and estimates for incurred but unreported claims	$ 1,293,000		1,293,000
SHC Risk Carriers, Inc | Professional malpractice liability insurance
Malpractice Insurance [Line Items]
Insurance policy coverage limits per claim			500,000
Malpractice insurance annual sublimit per center			1,000,000
Aggregate policy limit			5,000,000
Other Insurance
Insurance policy coverage limits per claim			500,000
Unaffiliated entities | Professional malpractice liability insurance
Malpractice Insurance [Line Items]
Insurance policy coverage limits per claim			1,000,000
Malpractice insurance annual sublimit per center			$ 3,000,000
Number of types of professional liability insurance policies | policy	7		7
Other Insurance
Insurance policy coverage limits per claim			$ 1,000,000
Scheduled for trial or arbitration over next 12 months
Malpractice Insurance [Line Items]
Number of professional liability lawsuits | lawsuit	7		7
TEXAS
Hurricane Harvey and Irma
Number of locations impacted by catastrophe | center			4
FLORIDA
Hurricane Harvey and Irma
Number of locations impacted by catastrophe | center			1