Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		$ 16,131	$ 17,130
Cash [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		876	737
Equity Securities US Companies [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		9,600	8,729
Equity Securities International Companies [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		404	274
Equity Funds [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets	[1]	195	1,861
US Government Corporations and Agencies Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		104	107
US States and Political Subdivisions Debt Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		233	365
External Credit Rating, Investment Grade [Member] | Corporate Debt Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets	[2]	4,719	5,057
Fair Value, Inputs, Level 1 [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		11,075	11,601
Fair Value, Inputs, Level 1 [Member] | Cash [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		876	737
Fair Value, Inputs, Level 1 [Member] | Equity Securities US Companies [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		9,600	8,729
Fair Value, Inputs, Level 1 [Member] | Equity Securities International Companies [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		404	274
Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets	[1]	195	1,861
Fair Value, Inputs, Level 1 [Member] | US Government Corporations and Agencies Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 1 [Member] | External Credit Rating, Investment Grade [Member] | Corporate Debt Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets	[2]	0	0
Fair Value, Inputs, Level 2 [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		5,056	5,529
Fair Value, Inputs, Level 2 [Member] | Cash [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 2 [Member] | Equity Securities US Companies [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 2 [Member] | Equity Securities International Companies [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets	[1]	0	0
Fair Value, Inputs, Level 2 [Member] | US Government Corporations and Agencies Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		104	107
Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		233	365
Fair Value, Inputs, Level 2 [Member] | External Credit Rating, Investment Grade [Member] | Corporate Debt Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets	[2]	4,719	5,057
Fair Value, Inputs, Level 3 [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 3 [Member] | Cash [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 3 [Member] | Equity Securities US Companies [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 3 [Member] | Equity Securities International Companies [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 3 [Member] | Equity Funds [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets	[1]	0	0
Fair Value, Inputs, Level 3 [Member] | US Government Corporations and Agencies Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets		0	0
Fair Value, Inputs, Level 3 [Member] | External Credit Rating, Investment Grade [Member] | Corporate Debt Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Fair Value Measurements [Line Items]
Fair value, plan assets	[2]	$ 0	$ 0

[1] This category comprises actively managed equity funds invested in large-cap and mid-cap U.S. companies.

[2] This category represents investment grade bonds of U.S. issuers from diverse industries.