Note 12 - Goodwill and Other Intangible Assets - Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Finite-lived intangible assets, gross	$ 131,800	$ 86,000
Less accumulated amortization	(26,700)	(20,900)
Total identifiable intangible assets, net	105,100	65,100
Noncompete Agreements [Member]
Finite-lived intangible assets, gross	$ 6,400	200
Weighted average amortization period (Year)	6 years 10 months 24 days
Customer Relationships [Member]
Finite-lived intangible assets, gross	$ 111,000	75,300
Weighted average amortization period (Year)	11 years 7 months 6 days
Trade Names [Member]
Finite-lived intangible assets, gross	$ 3,900	0
Weighted average amortization period (Year)	2 years
LDC Network Access [Member]
Finite-lived intangible assets, gross	$ 10,500	$ 10,500
Weighted average amortization period (Year)	10 years