Note 4 - Fair Value Measurements - Fair Value Estimate Calculation (Details) - North America Reporting Unit [Member]	Sep. 30, 2019	Dec. 31, 2018
Valuation Technique, Discounted Cash Flow [Member]
Valuation Method Allocation Of Use Percentage	75.00%	75.00%
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Long-term Revenue Growth Rate [Member]
Goodwill Impairment, Measurement Input	0.015	0.026
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, EBITDA Margins [Member]
Goodwill Impairment, Measurement Input	0.039	0.076
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Cost of Equity Capital [Member]
Goodwill Impairment, Measurement Input	0.154	0.142
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Cost of Debt [Member]
Goodwill Impairment, Measurement Input	0.04	0.037
Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Weighted Average Cost of Capital [Member]
Goodwill Impairment, Measurement Input	0.14	0.13
Valuation, Market Approach [Member]
Valuation Method Allocation Of Use Percentage	25.00%	25.00%
Valuation, Market Approach [Member] | Measurement Input, Revenue Multiple [Member]
Goodwill Impairment, Measurement Input	0.3	0.4
Valuation, Market Approach [Member] | Measurement Input, EBITDA Multiple [Member] | Minimum [Member]
Goodwill Impairment, Measurement Input	7	5.1
Valuation, Market Approach [Member] | Measurement Input, EBITDA Multiple [Member] | Maximum [Member]
Goodwill Impairment, Measurement Input	8	5.7
Valuation, Market Approach [Member] | Measurement Input, Invested Capital Control Premium [Member]
Goodwill Impairment, Measurement Input	0.25	0.25