Note 2 - Revenue - Revenues Disaggregated by Revenue Source and Market (Details) - USD ($) $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	[1]	Mar. 31, 2018	Dec. 31, 2017	[2]	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues	$ 155,828	$ 154,246	$ 146,791		$ 141,425	$ 148,493		$ 125,673	$ 133,313	$ 113,733	$ 598,290	$ 521,212	$ 489,720
Sales Channel, Commercial [Member]
Revenues											323,150
Sales Channel, State [Member]
Revenues											233,921
Sales Channel, Federal [Member]
Revenues											41,219
Coordination of Benefits [Member]
Revenues											397,095
Payment Integrity [Member]
Revenues											144,063
Total Population Management [Member]
Revenues											$ 57,132

[1] Second quarter 2018 results include the Company's entry into the Settlement Agreement for the payment of $20 million, as described in Note 14.

[2] Fourth quarter 2017 results include a non-cash tax benefit of $15.1 million due to the revaluation of the Company’s deferred tax balances pursuant to the tax rate reduction included in the 2017 Tax Act.