CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Held to maturity, fair value	$ 353,919	$ 414,470
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	120,000,000	60,000,000
Common stock, shares issued (in shares)	47,402,935	47,032,259
Common stock, shares outstanding (in shares)	47,269,692	46,917,735