Other Assets and Other liabilities - Summary of Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Assets And Other Liabilities [Abstract]
Deferred compensation	$ 5,301	$ 6,710
Accrued payroll	11,018	5,987
Mortgage servicing escrows	3,341	1,079
Mortgage buyback reserve	3,386	2,659
Accrued interest	1,504	632
Derivatives	1,699	586
Deferred tax liability (See Note 15)	11,858	4,180
Right to repurchase GNMA loans serviced (See Note 1)	43,035
Other liabilities	37,852	36,535
Total other liabilities	$ 118,994	$ 58,368