CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Investment securities held to maturity	$ 611,933	$ 632,380
Common Stock, stated value (in dollars per share)	$ 0.125	$ 0.125
Common Stock, shares authorized	50,000,000	50,000,000
Common Stock, shares issued	40,912,697	40,664,259
Common Stock, shares outstanding	40,912,697	40,664,259
Preferred Stock, par value (in dollars per share)	$ 1,000	$ 1,000
Preferred Stock, liquidation value (in dollars per share)	$ 1,000	$ 1,000
Preferred Stock, shares authorized	600	600
Preferred Stock, shares issued	125	125
Preferred Stock, shares outstanding	125	125