Note 5 - Business Segments - Summary of Financial Information by Reporting Segment (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Net patient revenues									$ 947,872,000	$ 932,774,000	$ 916,742,000
Other revenues									48,511,000	47,575,000	47,153,000
Net operating revenues	$ 253,880,000	$ 247,067,000	$ 247,151,000	$ 248,285,000	$ 248,920,000	$ 246,326,000	$ 242,142,000	$ 242,961,000	996,383,000	980,349,000	963,895,000
Costs and Expenses:
Salaries, wages and benefits									592,831,000	582,721,000	572,043,000
Other operating									268,442,000	254,038,000	249,833,000
Facility rent									40,518,000	40,923,000	40,367,000
Depreciation and amortization									42,419,000	41,894,000	42,652,000
Interest									3,135,000	4,697,000	4,890,000
Total costs and expenses									947,345,000	924,273,000	909,785,000
Income (loss) before non-operating income	16,497,000	6,568,000	10,189,000	15,784,000	17,194,000	10,834,000	12,165,000	15,883,000	49,038,000	56,076,000	54,110,000
Non-operating income (loss)									26,747,000	17,670,000	20,439,000
Unrealized gains on marketable equity securities	$ (3,866,000)	$ 9,312,000	$ (54,000)	$ 6,838,000	$ 721,000	$ 3,486,000	$ 12,448,000	$ (15,517,000)	12,230,000	1,138,000	0
Income before income taxes									88,015,000	74,884,000	74,549,000
Inpatient Services Segment [Member]
Revenues:
Net patient revenues									893,201,000	872,912,000	853,662,000
Other revenues									910,000	2,494,000	663,000
Net operating revenues									894,111,000	875,406,000	854,325,000
Costs and Expenses:
Salaries, wages and benefits									526,430,000	513,647,000	501,510,000
Other operating									242,435,000	225,133,000	221,414,000
Facility rent									32,748,000	33,052,000	32,744,000
Depreciation and amortization									38,731,000	38,372,000	38,246,000
Interest									1,578,000	1,504,000	1,719,000
Total costs and expenses									841,922,000	811,708,000	795,633,000
Income (loss) before non-operating income									52,189,000	63,698,000	58,692,000
Non-operating income (loss)									0	0	0
Unrealized gains on marketable equity securities									0	0
Income before income taxes									52,189,000	63,698,000	58,692,000
Homecare Services Segment [Member]
Revenues:
Net patient revenues									54,671,000	59,862,000	63,080,000
Other revenues									0	0	0
Net operating revenues									54,671,000	59,862,000	63,080,000
Costs and Expenses:
Salaries, wages and benefits									33,037,000	33,339,000	33,059,000
Other operating									17,003,000	19,566,000	20,855,000
Facility rent									1,854,000	1,945,000	1,980,000
Depreciation and amortization									250,000	229,000	177,000
Interest									0	0	0
Total costs and expenses									52,144,000	55,079,000	56,071,000
Income (loss) before non-operating income									2,527,000	4,783,000	7,009,000
Non-operating income (loss)									0	0	0
Unrealized gains on marketable equity securities									0	0
Income before income taxes									2,527,000	4,783,000	7,009,000
Other Segments [Member]
Revenues:
Net patient revenues									0	0	0
Other revenues									47,601,000	45,081,000	46,490,000
Net operating revenues									47,601,000	45,081,000	46,490,000
Costs and Expenses:
Salaries, wages and benefits									33,364,000	35,735,000	37,474,000
Other operating									9,004,000	9,339,000	7,564,000
Facility rent									5,916,000	5,926,000	5,643,000
Depreciation and amortization									3,438,000	3,293,000	4,229,000
Interest									1,557,000	3,193,000	3,171,000
Total costs and expenses									53,279,000	57,486,000	58,081,000
Income (loss) before non-operating income									(5,678,000)	(12,405,000)	(11,591,000)
Non-operating income (loss)									26,747,000	17,670,000	20,439,000
Unrealized gains on marketable equity securities									12,230,000	1,138,000
Income before income taxes									$ 33,299,000	$ 6,403,000	$ 8,848,000