Note 4 - Other Revenues - Summary of Other Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Rental income	$ 5,553	$ 5,515	$ 11,086	$ 11,001
Management and accounting services fees	3,738	3,752	7,446	7,611
Insurance services	1,955	2,087	3,646	3,644
Other	242	256	579	638
Total other revenues	$ 11,488	$ 11,610	$ 22,757	$ 22,894