Deposits - Certificates of deposits and Scheduled maturities of time deposits - (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits Disclosure Abstract
Aggregate amounts of certificates of deposits in denominations of $250,000 or more	$ 325,300	$ 83,700
Traditional, out-of-market brokered deposits	43,600	$ 2,900
Scheduled maturities of time deposits of all denominations
2018	1,131,167
2019	330,359
2020	111,836
2021	119,104
2022	40,581
Thereafter	8,261
Time deposits	$ 1,741,308