Note 7 - Revenues (Details Textual) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01 T in Millions	Mar. 31, 2019 T
Fixed Priced Contracts [Member]
Revenue, Remaining Performance Obligation, Mass	1.2
Contracts with Indexed Based Pricing Mechanisms [Member]
Revenue, Remaining Performance Obligation, Mass	0.1