Note 10 - Restructuring Costs (Details Textual)	3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2011 USD ($)
Asset Impairment Charges		$ 469,000					$ 8,247,000		$ 427,000	$ 1,000,000
Impairment of Real Estate				$ 400,000	$ 7,100,000
Number of Real Estate Properties Sold During Period		2	1					4
Real Estate Held-for-sale		$ 1,200,000	$ 1,000,000					$ 6,100,000
Number of Real Estate Properties Put Back into Service	1
Real Estate Previously Held-for-sale Put Back Into Service	$ 1,400,000
Operating Segments [Member]
Restructuring and Related Cost, Incurred Cost					8,100,000
Operating Segments [Member] | Selling, General and Administrative Expenses [Member]
Asset Impairment Charges					$ 2,700,000
Impairment of Real Estate							$ 5,000,000