Mortgage Banking Activities Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Mortgage Banking Revenue [Abstract]
Net realized gains on sale of mortgage loans	$ 36,300	$ 8,971	$ 70,126	$ 24,838
Net change in unrealized gain (loss) on mortgage loans held for sale	(1,672)	97	6,913	965
Net change in the fair value of mortgage loan commitments	1,593	514	23,991	4,733
Net change in the fair value of forward sales contracts	2,210	4,232	(1,844)	3,015
Total production revenue	38,431	13,814	99,186	33,551
Servicing revenue	13,528	16,366	43,876	48,594
Total mortgage banking revenue	$ 51,959	$ 30,180	$ 143,062	$ 82,145