Note 5 - Business Segments - Summary of Financial Information by Reporting Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net patient revenues									$ 919,843	$ 880,724	$ 864,846
Other revenues									47,153	45,914	41,776
Net operating revenues	$ 246,311	$ 241,985	$ 239,457	$ 239,243	$ 238,000	$ 231,281	$ 227,769	$ 229,588	966,996	926,638	906,622
Salaries, wages and benefits									572,043	548,007	532,735
Other operating									252,934	233,833	227,072
Facility rent									40,367	41,292	39,967
Depreciation and amortization									42,652	39,023	37,114
Interest									4,890	3,941	2,608
Total costs and expenses									912,886	866,096	839,496
Income before non–operating income	$ 16,323	$ 9,785	$ 12,138	$ 15,864	$ 17,687	$ 10,590	$ 14,641	$ 17,624	54,110	60,542	67,126
Non–operating income									20,439	19,665	18,148
Income before income taxes									74,549	80,207	85,274
Inpatient Services Segment [Member]
Net patient revenues									856,763	817,068	799,409
Other revenues									663	651	626
Net operating revenues									857,426	817,719	800,035
Salaries, wages and benefits									501,510	480,058	461,216
Other operating									224,515	205,885	198,585
Facility rent									32,744	33,129	32,072
Depreciation and amortization									38,246	34,423	32,451
Interest									1,719	1,921	2,112
Total costs and expenses									798,734	755,416	726,436
Income before non–operating income									58,692	62,303	73,599
Non–operating income
Income before income taxes									58,692	62,303	73,599
Homecare Services Segment [Member]
Net patient revenues									63,080	63,656	65,437
Other revenues
Net operating revenues									63,080	63,656	65,437
Salaries, wages and benefits									33,059	32,597	33,740
Other operating									20,855	20,705	20,600
Facility rent									1,980	1,932	1,863
Depreciation and amortization									177	190	211
Interest
Total costs and expenses									56,071	55,424	56,414
Income before non–operating income									7,009	8,232	9,023
Non–operating income
Income before income taxes									7,009	8,232	9,023
Other Segments [Member]
Net patient revenues
Other revenues									46,490	45,263	41,150
Net operating revenues									46,490	45,263	41,150
Salaries, wages and benefits									37,474	35,352	37,779
Other operating									7,564	7,243	7,887
Facility rent									5,643	6,231	6,032
Depreciation and amortization									4,229	4,410	4,452
Interest									3,171	2,020	496
Total costs and expenses									58,081	55,256	56,646
Income before non–operating income									(11,591)	(9,993)	(15,496)
Non–operating income									20,439	19,665	18,148
Income before income taxes									$ 8,848	$ 9,672	$ 2,652