Basis of Presentation and Significant Accounting Policies (Narrative) (Details)			3 Months Ended		12 Months Ended
	Jan. 01, 2019 USD ($)	Apr. 29, 2016 Hospital	Mar. 31, 2019 USD ($) Hospital state bed	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2014 Hospital
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of hospitals owned or leased | Hospital			27
Number of states in which entity operates | state			14
Number of licensed beds | bed			2,604
Increase (decrease) in net operating revenues during period for transaction price adjustments related to estimated cost report settlements			$ 1,800,000	$ 500,000
Net operating revenues			442,805,000	486,820,000
Provider taxes			33,964,000	33,055,000
Gross amounts of charity care revenues			5,000,000	13,300,000
Accounts receivable, net of contractual adjustments			326,639,000		$ 322,608,000
Due from third-party payors			67,748,000		63,443,000
General and administrative costs			12,600,000	14,900,000
Severance costs			1,490,000	1,898,000
Electronic health records incentives			26,000	(141,000)
Operating lease right-of-use assets			89,638,000		0
Operating lease liabilities			93,348,000
Acquired finite-lived intangible asset, residual value			$ 0
New date of annual goodwill impairment test			The Company performs its annual testing of impairment for goodwill in the fourth quarter of each year.
Noncontrolling interests and redeemable noncontrolling interests			The Company’s consolidated financial statements include all assets, liabilities, revenues and expenses of less than 100% owned entities that it controls.
Maximum period during which assets held for sale sold			12 months
Accrued Salaries and Benefits [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Undiscounted reserve for self-insured employee health benefits			$ 9,800,000		10,400,000
Capitalized Internal Use Software, Except Significant System Conversions [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Finite-lived intangible assets, useful life			3 years
Community Health Systems, Inc [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of Hospitals | Hospital						4
Equipment Leases [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Operating lease, initial term			3 years
Accounting Standards Update 2016-02 [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Operating lease right-of-use assets	$ 93,700,000
Operating lease liabilities	95,600,000
Cumulative effect adjustment that increased accumulated deficit	$ 700,000
Maximum [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Electronic health records incentives			$ 100,000
Maximum [Member] | Capitalized Internal Use Software, Significant System Conversions [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Finite-lived intangible assets, useful life			10 years
Maximum [Member] | Real Estate Leases [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Operating lease, initial term			10 years
Operating lease, renewal term			10 years
Maximum [Member] | Land Improvements [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of asset			20 years
Maximum [Member] | Buildings and Improvements [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of asset			40 years
Maximum [Member] | Equipment and Fixtures [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of asset			18 years
Minimum [Member] | Capitalized Internal Use Software, Significant System Conversions [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Finite-lived intangible assets, useful life			8 years
Minimum [Member] | Real Estate Leases [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Operating lease, initial term			5 years
Operating lease, renewal term			5 years
Minimum [Member] | Land Improvements [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of asset			3 years
Minimum [Member] | Buildings and Improvements [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of asset			5 years
Minimum [Member] | Equipment and Fixtures [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Estimated useful life of asset			3 years
General and Administrative Expense [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Severance costs			$ 0	1,900,000
Illinois [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of hospitals owned or leased | Hospital			8
Net operating revenues			$ 165,224,000	187,753,000
California [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of hospitals owned or leased | Hospital			2
Net operating revenues			$ 44,164,000	44,965,000
California Hospital Quality Assurance Fee [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Net operating revenues			8,100,000	7,900,000
Provider taxes			2,200,000	2,100,000
Illinois Hospital Credit Program [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Net operating revenues			2,000,000	0
Medicare [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Net operating revenues			129,046,000	144,583,000
Accounts receivable, net of contractual adjustments			56,300,000		58,200,000
Medicaid [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Net operating revenues			81,924,000	85,103,000
Medicaid [Member] | Illinois [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Accounts receivable, net of contractual adjustments			24,400,000		24,500,000
Medicaid [Member] | California [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Due from third-party payors			41,700,000		$ 37,800,000
Hospital Operations Reporting Unit [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Net operating revenues			$ 426,153,000	$ 467,166,000
Sales Revenue, Segment [Member] | Segment Concentration Risk [Member] | Hospital Operations Reporting Unit [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Concentration risk, percentage			95.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Medicare [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Concentration risk, percentage			17.20%		18.00%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Medicaid [Member] | Illinois [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Concentration risk, percentage			7.50%		7.60%
Supplemental Program Receivables | Credit Concentration Risk [Member] | Medicaid [Member] | California [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Concentration risk, percentage			61.60%		59.60%
Spin-off from CHS [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of hospitals owned or leased | Hospital		38
Percentage ownership of number of stock shares held by the parent		100.00%
Record date for stockholders of the parent to be eligible to receive share distribution in spin-off		Apr. 22, 2016