Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Mortgage servicing rights	$ 41,990	$ 72,532	$ 81,012
Mortgage banking, net	17,704	63	$ (545)
Equity Securities without Readily Determinable Fair Value, Amount	13,000	13,000
Equity securities	15,106	15,090
Fair Value, Inputs, Level 3
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Equity Securities without Readily Determinable Fair Value, Amount	13,444	13,444
Equity securities	13,444	13,444
Fair Value, Measurements, Nonrecurring | Fair Value, Inputs, Level 2
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
OREO(b)	6,125	3,565
Other noninterest expense	3,747	1,860
Fair Value, Measurements, Nonrecurring | Fair Value, Inputs, Level 3
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Individually evaluated loans(a)	138,752	45,792
Provision for credit losses	(97,519)	(66,172)
Mortgage servicing rights	41,990	72,532
Mortgage banking, net	$ (17,704)	(63)
Equity Securities without Readily Determinable Fair Value, Amount		13,444
Equity securities		$ 13,444