Note 6 - Goodwill and Intangible Assets - Summary of Acquired Amortizable Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 198,495	$ 18,328
Accumulated Amortization	(6,536)	(4,460)
Net Carrying Amount	191,959	13,868
Internal-use Software [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,034	7,074
Accumulated Amortization	(2,636)	(1,810)
Net Carrying Amount	$ 4,398	$ 5,264
Technology-based Intangibles [Member]
Finite Lived Intangible Assets [Line Items]
Amortization Period (Year)	20 years	20 years
Gross Carrying Amount	$ 3,519	$ 3,646
Accumulated Amortization	(1,496)	(1,413)
Net Carrying Amount	2,023	2,233
Customer-related Intangibles [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	187,942	7,608
Accumulated Amortization	(2,404)	(1,237)
Net Carrying Amount	$ 185,538	$ 6,371
Minimum [Member] | Internal-use Software [Member]
Finite Lived Intangible Assets [Line Items]
Amortization Period (Year)	3 years	3 years
Minimum [Member] | Customer-related Intangibles [Member]
Finite Lived Intangible Assets [Line Items]
Amortization Period (Year)	10 years	10 years
Maximum [Member] | Internal-use Software [Member]
Finite Lived Intangible Assets [Line Items]
Amortization Period (Year)	7 years	7 years
Maximum [Member] | Customer-related Intangibles [Member]
Finite Lived Intangible Assets [Line Items]
Amortization Period (Year)	15 years	15 years