Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Investment securities held to maturity; fair value	$ 158,219	$ 150,932
Common stock, par value (in usd per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	50,435,663	47,486,250