Shareholders' Equity And Earnings Per Share (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Thousands						1 Months Ended				3 Months Ended		6 Months Ended		12 Months Ended
	May. 21, 2015	May. 07, 2015	Feb. 19, 2015	Feb. 05, 2015	Dec. 19, 2008	Jun. 30, 2015	Apr. 30, 2015	Jan. 31, 2015	Mar. 31, 2012	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Jun. 25, 2015
Temporary Equity [Line Items]
Cash dividends declared per common share (in usd per share)							$ 0.11	$ 0.11		$ 0.11	$ 0.10	$ 0.22	$ 0.20
Common stock dividends per share declared annualized							$ 0.44	$ 0.44
Dividends payable, date to be paid	May 21, 2015		Feb. 19, 2015
Dividends payable, date of record		May 07, 2015		Feb. 05, 2015
Delavan Bancshares
Temporary Equity [Line Items]
Common stock, shares issued, acquisition								422,121
US Treasury [Member]
Temporary Equity [Line Items]
Warrants outstanding					1,643,295	557,068				557,068		557,068
Investment warrants, exercise price					$ 22.82
Warrant termination period					10 years
Warrants exercised												380,349
Common stock, shares, issued from exercise of warrant shares												203,887
Series D Preferred Stock
Temporary Equity [Line Items]
Preferred stock, shares issued															5,000,000,000,000
Preferred stock, liquidation value per share						$ 25				$ 25	$ 0	$ 25	$ 0	$ 0	$ 25
Preferred stock, value						$ 125,000				$ 125,000	$ 0	$ 125,000	$ 0	$ 0	$ 125,000
Preferred stock, Dividend payment terms						quarterly
Preferred stock, dividend rate, percentage						6.50%
Series C Preferred Stock
Temporary Equity [Line Items]
Preferred stock, shares issued									126,500
Preferred stock, liquidation value per share						$ 1,000			$ 1,000	$ 1,000	$ 1,000	$ 1,000	$ 1,000	$ 1,000
Preferred stock, value						$ 126,312			$ 126,500	$ 126,312	$ 126,467	$ 126,312	$ 126,467	$ 126,467
Preferred stock, Dividend payment terms									quarterly
Preferred stock, dividend rate, percentage									5.00%
Convertible preferred stock, terms of conversion									24.3132
Preferred stock, shares converted												155		10
Common stock, shares, conversion of preferred stock												3,767		244
London Interbank Offered Rate (LIBOR) [Member] | Series D Preferred Stock
Temporary Equity [Line Items]
Preferred stock, dividend rate, percentage, variable spread						4.06%