Deposits - Schedule of Deposit Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Less than one year	$ 907,820	$ 669,610
More than one years to two years	462,826	474,475
More than two years to three years	215,777	169,069
More than three years to four years	31,358	68,184
More than four years	12,590	22,544
Total term certificate accounts	$ 1,630,371	$ 1,403,882