Note 9 - Borrowed Funds - Comparative Data for Securities Sold Under Agreements to Repurchase (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Average amount outstanding during the year (1)	[1]	$ 381,967	$ 400,822	$ 629,315
Maximum amount outstanding at month-end (2)	[2]	400,000	400,000	700,000
Balance, December 31		$ 350,000	$ 400,000	$ 450,000
Rate, December 31		4.06%	3.89%	3.85%
Weighted average interest rate for the year		4.01%	3.95%	3.92%

[1] Average balances were computed using daily averages.

[2] Highest month-end balances were January 2016, January 2015, and January 2014.