Mortgage Banking Activities Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Mortgage Banking Revenue [Abstract]
Net realized gains on sale of mortgage loans	$ 16,177	$ 36,300	$ 62,960	$ 70,126
Net change in unrealized gain (loss) on mortgage loans held for sale	(1,365)	(1,672)	(6,537)	6,913
Net change in the fair value of mortgage loan commitments	(1,953)	1,593	(12,186)	23,991
Net change in the fair value of forward sales contracts	2,544	2,210	6,457	(1,844)
Total production revenue	15,403	38,431	50,694	99,186
Servicing revenue	10,883	13,528	33,924	43,876
Total mortgage banking revenue	$ 26,286	$ 51,959	$ 84,618	$ 143,062