Note 5 - Long-term Debt - Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Principal	$ 498,376	$ 496,492
Deferred Financing Costs, Net	(13,221)	(13,878)
Balance	485,155	482,614
Principal, Current	(14,128)	(11,255)
Deferred Financing Costs, Net, Current	0	0
Balance, Current	(14,128)	(11,255)
Principal, Non-current	484,248	485,237
Deferred Financing Costs, Net, Non-current	(13,221)	(13,878)
Balance, Non-current	471,027	471,359
Revolving Credit Facility [Member]
Principal	45,000	45,000
Deferred Financing Costs, Net	(303)	(341)
Balance	44,697	44,659
Notes Payable, Other Payables [Member]
Principal	1,684	1,684
Deferred Financing Costs, Net	0	0
Balance	1,684	1,684
Term Facility [Member]
Principal	281,796	280,993
Deferred Financing Costs, Net	(9,138)	(9,492)
Balance	272,658	271,501
First Senior Secured Credit Agreement [Member]
Principal	107,695	107,695
Deferred Financing Costs, Net	(1,734)	(1,784)
Balance	105,961	105,911
Second Senior Secured Credit Agreement [Member]
Principal	61,120	61,120
Deferred Financing Costs, Net	(2,046)	(2,261)
Balance	59,074	58,859
Other Debt [Member]
Principal	1,081	0
Deferred Financing Costs, Net	0	0
Balance	$ 1,081	$ 0