Other Noninterest Expense - Summary of Other Noninterest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Income and Expenses [Abstract]
Lending and other client related processing costs	$ 5,177	$ 3,201
Correspondent bank fees	3,744	3,410
Correspondent bank fees	4,185	0
Trade order execution costs	2,516	0
Data processing services	2,899	2,492
Telephone	2,741	2,377
Dues and publications	1,524	850
Postage and supplies	770	667
Other	9,980	5,107
Total other noninterest expense	$ 33,536	$ 18,104