Deposits - Maturities of deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deposits
Due within one year	$ 2,084,369
Due in one year to two years	57,085
Due in two years to three years	25,038
Due in three years to four years	6,284
Due in four years to five years	1,563
Total time deposits	2,174,339	$ 680,454
Certificates of deposit of 250,000 or more	$ 128,900	$ 46,700