Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Securities Held-to-Maturity, Fair Value	$ 105,642	$ 55,320
Accumulated amortization and fair value adjustments on other intangibles	$ 24,423	$ 21,825
Common stock, par value	$ 5	$ 5
Common stock, shares authorized	48,000,000	48,000,000
Common stock, shares issued	31,556,799	31,556,799
Common stock, shares outstanding	29,407,076	29,334,859
Treasury stock, shares	2,149,723	2,221,940