Note 13 - Employee Retirement Plans - Domestic Defined Benefit Plan Assets (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair value of plan assets		$ 3,225,000	$ 3,058,000	$ 3,263,000
United States Pension Plan of US Entity [Member]
Fair value of plan assets		2,765,000	2,616,000	2,814,000
United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets		412,000	359,000
United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		2,066,000	2,033,000
United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets		287,000	224,000
Equity Securities [Member] | United States Pension Plan of US Entity [Member] | U.S. Companies [Member]
Fair value of plan assets		318,000	336,000
Equity Securities [Member] | United States Pension Plan of US Entity [Member] | U.S. Companies [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets		47,000	51,000
Equity Securities [Member] | United States Pension Plan of US Entity [Member] | U.S. Companies [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		271,000	285,000
Equity Securities [Member] | United States Pension Plan of US Entity [Member] | U.S. Companies [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets
Equity Securities [Member] | United States Pension Plan of US Entity [Member] | International Companies [Member]
Fair value of plan assets		340,000	322,000
Equity Securities [Member] | United States Pension Plan of US Entity [Member] | International Companies [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets		90,000	79,000
Equity Securities [Member] | United States Pension Plan of US Entity [Member] | International Companies [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		250,000	243,000
Equity Securities [Member] | United States Pension Plan of US Entity [Member] | International Companies [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets
Fixed Income Securities [Member] | United States Pension Plan of US Entity [Member] | U.S. Companies [Member]
Fair value of plan assets		1,608,000	1,566,000
Fixed Income Securities [Member] | United States Pension Plan of US Entity [Member] | U.S. Companies [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets		175,000	158,000
Fixed Income Securities [Member] | United States Pension Plan of US Entity [Member] | U.S. Companies [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets		1,433,000	1,408,000
Fixed Income Securities [Member] | United States Pension Plan of US Entity [Member] | U.S. Companies [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets
Private Equity Funds [Member]
Fair value of plan assets		137,000	163,000	192,000
Private Equity Funds [Member] | United States Pension Plan of US Entity [Member]
Fair value of plan assets	[1]	137,000	163,000
Private Equity Funds [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets	[1]
Private Equity Funds [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	[1]
Private Equity Funds [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets	[1]	137,000	163,000
Real Estate [Member]
Fair value of plan assets		150,000	61,000	$ 84,000
Real Estate [Member] | United States Pension Plan of US Entity [Member]
Fair value of plan assets	[2]	150,000	61,000
Real Estate [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets	[2]
Real Estate [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	[2]
Real Estate [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets	[2]	150,000	61,000
Cash Equivalents [Member] | United States Pension Plan of US Entity [Member]
Fair value of plan assets		100,000	71,000
Cash Equivalents [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets		100,000	71,000
Cash Equivalents [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets
Cash Equivalents [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets
Commodity Option [Member] | United States Pension Plan of US Entity [Member]
Fair value of plan assets	[3]	112,000	97,000
Commodity Option [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of plan assets	[3]
Commodity Option [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of plan assets	[3]	112,000	97,000
Commodity Option [Member] | United States Pension Plan of US Entity [Member] | Fair Value, Inputs, Level 3 [Member]
Fair value of plan assets	[3]

[1] This category includes venture capital, leverage buyouts and distressed debt limited partnerships invested primarily in U.S. companies. The inputs are valued by discounted cash flow analysis and comparable sale analysis.

[2] This category includes industrial, office, apartments, hotels, infrastructure and retail investments which are limited partnerships predominately in the U.S. The inputs are valued by discounted cash flow analysis; comparable sale analysis and periodic external appraisals.

[3] This category includes investments in energy, industrial metals, precious metals, agricultural and livestock primarily through futures, options, swaps and exchange traded funds.