Deposits - Brokered deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deposits
Brokered certificates of deposit	$ 1,962,389	$ 578,471
Brokered savings deposits	184,603	109,607
Brokered deposit on demand accounts	10,001	300,134
Total brokered deposits	$ 2,156,993	$ 988,212