Mortgage Banking - Capitalized Mortgage and Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Mortgage servicing assets:
Balance at beginning of period	$ 10,801	$ 10,419	$ 10,240
Loans sold, servicing retained	8,595	2,191	1,520
Mortgage servicing rights acquired	9,747
Amortization	(7,477)	(1,809)	(1,341)
Carrying value before valuation allowance at end of period	21,666	10,801	10,419
Valuation allowance:
Balance at beginning of period	(534)	(300)	(432)
Impairment recovery (charges)	(7,979)	(234)	132
Balance at end of period	(8,513)	(534)	(300)
Net carrying value of MSRs at end of period	13,153	10,267	10,119
Fair value of MSRs at end of period	$ 13,153	$ 10,378	$ 10,656