Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Shareholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000	10,000,000
Preferred stock, shares issued	0	0	0
Preferred stock, shares outstanding	0	0	0
Common stock, par value (in dollars per share)	$ 2.50	$ 2.50	$ 2.50
Common stock, shares authorized	40,000,000	40,000,000	40,000,000
Common stock, shares issued	24,211,793	24,150,702	24,135,220
Common stock, shares outstanding	24,211,793	24,150,702	24,135,220
Investment securities:
Securities held to maturity, fair value (in dollars)	$ 9,758	$ 10,233	$ 11,019
Other real estate owned
Other real estate owned, covered (in dollars)	5,465	16,227	18,961
Other real estate owned, non-covered (in dollars)	25,913	26,499	32,289
Credit impaired | Acquired loans
Loans:
Covered loans	103,329	182,464	197,944
Non-covered	665,277	736,938	782,548
Non-Credit impaired | Acquired loans
Loans:
Covered loans	7,990	9,376	9,459
Non-covered	$ 1,099,450	$ 1,318,623	$ 1,367,884