Note 17 - Share-based Compensation - Number of Shares to Be Issued Upon Exercise of Outstanding Stock-based Awards (Details) - $ / shares		Dec. 31, 2017	Dec. 31, 2016
Number of shares to be issued upon exercise (in shares)			124,000
Weighted average exercise price (in dollars per share)
Shares available for future issuance (in shares)		302,727	303,000
Stock Appreciation Rights (SARs) [Member]
Number of shares to be issued upon exercise (in shares)	[1]
Weighted average exercise price (in dollars per share)	[1]
Shares available for future issuance (in shares)	[2]		303,000
Restricted Stock [Member]
Number of shares to be issued upon exercise (in shares)			119,000
Weighted average exercise price (in dollars per share)
Shares available for future issuance (in shares)	[2]
Performance Shares [Member]
Number of shares to be issued upon exercise (in shares)	[3]
Weighted average exercise price (in dollars per share)
Shares available for future issuance (in shares)	[2]
Restricted Stock Units (RSUs) [Member]
Number of shares to be issued upon exercise (in shares)			5,000
Weighted average exercise price (in dollars per share)
Shares available for future issuance (in shares)	[2]

[1] At December 31, 2017, approximately 704,000 SARs were outstanding at a weighted average grant price of $19.51. The number of shares to be issued upon exercise will be determined based on the difference between the grant price and the market price at the date of exercise.

[2] Under the 2015 Omnibus Equity Compensation Plan, shares of stock are authorized for issuance as incentive and nonqualified stock options, SARs, restricted stock, and restricted stock units

[3] The number of shares to be issued is dependent upon Bancorp achieving certain predefined performance targets and ranges from zero shares to approximately 205,000 shares. As of December 31, 2017, the expected shares to be awarded are 155,497.