Note 1 - Basis of Presentation and Accounting Policies - Changes in Accumulated Other Comprehensive Income (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Beginning balance	$ 2,447,898	$ 3,168,000	$ 103,000
Other comprehensive income (loss) before reclassifications	(649,000)	159,000	3,073,000
Amounts reclassified from AOCI	(289,000)	(879,000)	(8,000)
Net current period other comprehensive income (loss)	(938,466)	(720,584)	3,065,601
Ending balance	1,509,432	2,447,898	3,168,000
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Beginning balance	2,695,000	3,422,000	125,000
Other comprehensive income (loss) before reclassifications	(973,000)	152,000	3,305,000
Amounts reclassified from AOCI	(289,000)	(879,000)	(8,000)
Net current period other comprehensive income (loss)	(1,262,000)	(727,000)	3,297,000
Ending balance	1,433,000	2,695,000	3,422,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Beginning balance	(247,000)	(254,000)	(22,000)
Other comprehensive income (loss) before reclassifications	324,000	7,000	(232,000)
Amounts reclassified from AOCI	0	0	0
Net current period other comprehensive income (loss)	324,000	7,000	(232,000)
Ending balance	$ 77,000	$ (247,000)	$ (254,000)