CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Securities held-to-maturity
Securities held-to-maturity, fair value (in dollars)	$ 394,292	$ 318,748
Preferred stock
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	38,200,883	37,941,007
Common stock, shares outstanding	38,200,883	37,941,007