Note 11 - Business Segments and Significant Customers (Details) - Long-lived Assets by Geographic Area (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Note 11 - Business Segments and Significant Customers (Details) - Long-lived Assets by Geographic Area [Line Items]
Long-lived assets	$ 1,831,564	$ 1,791,601
UNITED STATES
Note 11 - Business Segments and Significant Customers (Details) - Long-lived Assets by Geographic Area [Line Items]
Long-lived assets	1,081,699	1,053,374
CANADA
Note 11 - Business Segments and Significant Customers (Details) - Long-lived Assets by Geographic Area [Line Items]
Long-lived assets	749,810	738,172
MEXICO
Note 11 - Business Segments and Significant Customers (Details) - Long-lived Assets by Geographic Area [Line Items]
Long-lived assets	$ 55	$ 55