Condensed 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	$ 210,106	$ 208,273
Allowance for loan losses	$ 17,821	$ 17,820
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Common stock, par value
Common stock, shares authorized	99,000,000	99,000,000
Common stock, shares issued	45,077,816	38,400,476
Common stock, shares outstanding	45,052,747	38,375,407