Note 14 - Benefit Plans (Details Textual)	12 Months Ended
	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	4.00%
Defined Contribution Plan, Cost Recognized	$ 627,000	$ 546,000	$ 480,000
Annuity Payment, Maximum Contractual Term	10 years
Retirement Age to Be Attained to Receive Postretirement Benefits	65
Defined Benefit Pension Plan, Liabilities	$ 1,300,000	1,300,000
Pension and Other Postretirement Benefit Expense	$ 31,000	34,000	36,000
Deferred Compensation Plan, Benefits, Number of Years to Vest	3 years
Deferred Compensation Plan, Amount Vested	$ 974,000	851,000
Deferred Compensation Arrangement with Individual, Compensation Expense	$ 88,000	$ 15,000	$ 147,000
Deferred Compensation Plan, Shares Held | shares	25,437
Deferred Compensation Plan, Shares Acquired | shares	0	0	0
Other Assets [Member]
Cash Surrender Value of Life Insurance	$ 2,400,000	$ 2,300,000
Minimum [Member]
Annual Annuity Payments	15,000
Maximum [Member]
Annual Annuity Payments	$ 25,000