Note 3 - Coronavirus Pandemic (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Government Assistance Stimulus Income CARES Act	$ 10,429,000	$ 12,132,000	$ 48,304,000	$ 36,780,000
Proceeds from Medicare Accelerated and Advance Payment Program			51,253,000
Contract with Customer, Liability, Current	27,013,000		27,013,000		$ 51,253,000
Proceeds from Government Assistance Medicare Accelerated and Advance Payment Program			0
Revenue from Contract with Customer, Including Assessed Tax	254,817,000	227,383,000	708,648,000	697,149,000
Supplemental Medicaid Payments [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 5,053,000	$ 4,845,000	16,102,000	$ 10,378,000
Medicare Accelerated and Advance Payment Program [Member]
Proceeds from Government Assistance Medicare Accelerated and Advance Payment Program			$ 21,153,000