Deposits - Summary of Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Interest-bearing demand	$ 8,794	$ 4,523	$ 2,211
Money market	18,169	9,854	4,690
Savings	7,053	1,030	1,017
Time deposits	19,642	8,591	4,806
Total customer interest expense	53,658	23,998	12,724
Brokered deposits	6,417	5,070	2,180
Total interest expense on deposits	$ 60,075	$ 29,068	$ 14,904