Mortgage Banking - Capitalized Mortgage and Valuation Allowance (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Mortgage servicing assets:
Balance at beginning of period	$ 21,666	$ 10,801
Loans sold, servicing retained	2,374	1,376
Mortgage servicing rights acquired		9,747
Amortization	(2,344)	(1,163)
Carrying value before valuation allowance at end of period	21,696	20,761
Valuation allowance:
Balance at beginning of period	(8,513)	(534)
Impairment recovery (charges)	5,320	(4,485)
Balance at end of period	(3,193)	(5,019)
Net carrying value of MSRs at end of period	18,503	15,742
Fair value of MSRs at end of period	$ 18,695	$ 16,105