Mortgage Banking Activities Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Mortgage Banking Revenue [Abstract]
Net realized gains on sale of mortgage loans	$ 9,717	$ 5,693
Net change in unrealized gain on mortgage loans held for sale	3,561	(53)
Net change in the fair value of mortgage loan commitments	19,017	2,713
Net change in the fair value of forward sales contracts	(10,725)	(485)
Total production revenue	21,570	7,868
Servicing revenue	15,597	15,966
Total mortgage banking revenue	$ 37,167	$ 23,834