Note 2 - Significant Accounting Policies - Cash and Cash Equivalents, and Long Term Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash and cash equivalents	$ 56,689	$ 48,315	$ 49,241
Long term restricted cash included in other assets	547	488	467
Cash, cash equivalents and long term restricted cash shown in the consolidated statement of cash flows	$ 57,236	$ 48,803	$ 49,708	$ 76,904