Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Shareholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 2.50	$ 2.50
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	24,162,657	24,150,702
Common stock, shares outstanding	24,162,657	24,150,702
Investment securities:
Securities held to maturity, fair value (in dollars)	$ 9,723	$ 10,233
Other real estate owned
Other real estate owned, covered (in dollars)	5,751	16,227
Other real estate owned, non-covered (in dollars)	24,803	26,499
Acquired non-credit impaired loans
Loans:
Covered loans	8,047	9,376
Non-covered	1,041,491	1,318,623
Acquired credit impaired loans
Loans:
Covered loans	98,459	182,464
Non-covered	$ 635,411	$ 736,938