Note 6 - Acquisitions - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions			3 Months Ended		9 Months Ended
		Sep. 09, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Goodwill, Ending Balance			$ 3,924.9		$ 3,924.9		$ 3,864.3
Cash acquired			(5.2)	$ (3.1)	(5.2)	$ (6.8)
Net cash purchase price			$ (151.9)	$ (40.4)	(151.9)	$ (109.5)
Total intangible assets					$ 59.2
Technology [Member]
Weighted average useful life (Year)					6 years
Total intangible assets					$ 2.1
Marketing [Member]
Weighted average useful life (Year)					5 years
Total intangible assets					$ 1.2
Customer [Member]
Weighted average useful life (Year)					11 years
Total intangible assets					$ 55.9
Franco Signor [Member]
Cash and cash equivalents (1)	[1]	$ 10.9
Accounts receivable		2.6
Other current assets		0.5
Fixed assets		0.5
Operating lease right-of-use assets, net		1.5
Intangible assets		59.2
Goodwill, Ending Balance		99.9
Other assets		8.0
Total assets acquired		183.1
Current liabilities (1)	[1]	(6.4)
Deferred revenues		(0.4)
Operating lease liabilities		(1.4)
Deferred income tax, net		(1.8)
Other liabilities		(8.0)
Total liabilities assumed		(18.0)
Net assets acquired		165.1
Cash and cash equivalents	[1]	(10.9)
Restricted cash (1)	[1]	5.7
Cash acquired		(5.2)
Net cash purchase price		$ (159.9)

[1] Within cash and cash equivalents, there is $5.7 million of restricted cash related to Franco Signor's professional administrative services for Medicare Set Asides, with an offsetting liability of $5.7 million included within current liabilities.