Note 14 - Stockholders' Equity (Details Textual) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Common Stock, Shares Authorized	100,000,000	100,000,000
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Preferred Stock, Shares Authorized	5,000,000
Preferred Stock, Par or Stated Value Per Share	$ 0.10
Preferred Stock, Shares Outstanding	0	0
Treasury Stock, Shares	1,424,153	1,583,909
Common Stock, Capital Shares Reserved for Future Issuance	920,308
Nonvoting Common Stock [Member]
Common Stock, Shares Authorized	730,746	730,746
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares, Outstanding	0	0