CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Amortized cost of investment securities available for sale	$ 3,280,814	$ 3,515,401
Held-to-maturity Securities, Fair Value	$ 274,718	$ 256,314
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	107,629,478	107,057,520
Common stock, shares outstanding	105,876,371	105,487,365