An additional amount held in risk-based capital designed to ensure that banks build up capital buffers outside periods of stress which can be drawn down as losses are incurred. The requirement is based on simple capital conservation rules designed to avoid breaches of minimum capital requirements.

No definition available.

Note 11 - Regulatory Matters (Details Textual) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended		62 Months Ended
	Jun. 17, 2020	Apr. 16, 2020	Mar. 18, 2020	Jan. 16, 2020	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Dec. 31, 2019	May 31, 2019
Preferred Securities of Subsidiary Trust					$ 45.0		$ 45.0	$ 44.8
Maximum Restricted Core Element Allowed in Tier One Capital Percent					25.00%
Maximum Level of Consolidated Aggregate Assets Allowing for Inclusion of Trust Preferred Securities in Tier One Capital					$ 15,000.0		15,000.0
Trust Preferred Securities Included in Tier One Capital					$ 45.0		$ 45.0	$ 44.8
Capital Conservation Buffer					2.50%		2.50%
Common Equity Tier 1 Risk Based Capital Required For Capital Adequacy to Risk Weighted Assets					0.07		0.07
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets					0.085		0.085
Capital Required for Capital Adequacy to Risk Weighted Assets					0.105		0.105
Common Stock, Dividends, Per Share, Declared (in dollars per share)				$ 0.28
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share)			$ 0.28		$ 0.28	$ 0.26
Stock Repurchase Program, Authorized Amount									$ 20.0
Stock Repurchased During Period, Shares (in shares)					222,385		1,600,000
Stock Repurchased During Period, Value					$ 6.3		$ 38.9
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)					$ 28.25		$ 24.13
Stock Repurchase Program, Remaining Authorized Repurchase Amount					$ 10.1		$ 10.1
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)		$ 0.28
Forecast [Member]
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share)	$ 0.28