Note 6 - Income Taxes - Reconciliation of the U.S. Statutory Income Tax Rate to Effective Tax Rate (Details)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statutory U.S. income tax rate		35.00%	35.00%	35.00%
State income tax (benefit), net of federal effect		(0.30%)	0.10%	4.90%
Rate difference on foreign earnings (1)	[1]	(9.20%)	(19.80%)	(8.30%)
Uncertain tax positions		(0.10%)	4.30%	(0.10%)
Equity earnings impact		(0.40%)	(5.40%)	(2.00%)
Valuation allowances		1.20%	(4.20%)	0.80%
Realignment of Dow Corning interest (2)	[2]	(28.20%)
Other items, net		1.90%	(0.10%)	0.40%
Effective income tax (benefit) rate		(0.10%)	9.90%	30.70%

[1] Tax benefit is primarily for excess foreign tax credits resulting from the inclusion of foreign earnings in U.S. income and the income of subsidiaries with lower statutory rates than the U.S.

[2] Refer to Note 7 (Investments) of the Consolidated Financial Statements for additional detail.