Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Investment securities:
Securities held to maturity, fair value (in dollars)	$ 10,114	$ 10,233	$ 11,058
Other real estate owned
Other real estate owned, covered (in dollars)	8,172	16,227	21,998
Other real estate owned, non-covered (in dollars)	$ 26,870	$ 26,499	$ 31,735
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
Credit impaired | Acquired loans
Loans:
Covered loans	$ 113,158	$ 182,464	$ 243,942
Non-covered	710,823	736,938	803,394
Non-Credit impaired | Acquired loans
Loans:
Covered loans	8,059	9,376	7,538
Non-covered	$ 1,163,613	$ 1,318,623	$ 1,440,045