Note 15 - Stockholders' Equity (Details Textual) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Common stock, shares authorized (in shares)	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, at cost (in shares)	1,264,109	1,424,153
Common Stock, Capital Shares Reserved for Future Issuance	662,671
Nonvoting Common Stock [Member]
Common stock, shares authorized (in shares)	730,746	730,746
Common Stock, Par or Stated Value Per Share	$ 0.10	$ 0.10
Common Stock, Shares, Outstanding	0	0