Note 1 - Business and Significant Accounting Policies (Details) - Effect of Revision on Line Items in Condensed Consolidated Balance Sheet (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Mar. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred income taxes	$ 891		$ 17,181	$ 21,283
Property, plant and equipment	1,452,336		1,233,525	1,252,873
Total assets	2,159,433	[1]	2,133,925	2,087,523	[1]	2,314,718	[1]
Accumulated deficit	(3,088)		(49,360)	(44,326)
Total equity	745,111		696,876	695,607		906,644
Total liabilities and equity	2,159,433		2,133,925	2,087,523
Scenario, Previously Reported [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred income taxes			52,939	53,989
Property, plant and equipment			1,207,410	1,226,758
Total assets			2,143,568	2,094,114
Accumulated deficit			(39,717)	(37,735)
Total equity			706,519	702,189
Total liabilities and equity			2,143,568	2,094,114
Restatement Adjustment [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred income taxes			(35,758)	(32,706)
Property, plant and equipment			26,115	26,115
Total assets			(9,643)	(6,591)
Accumulated deficit			(9,643)	(6,591)
Total equity			(9,643)	(6,591)
Total liabilities and equity			$ (9,643)	$ (6,591)

[1] Including unconsolidated investments