Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Mortgage Banking Revenue [Abstract]
Net realized gains on sales of mortgage loans	$ 39,730	$ 36,379	$ 45,128
Net change in unrealized gain on mortgage loans held for sale	672	(674)	2,031
Net change in fair value of mortgage loan commitments	(145)	(1,145)	(3,210)
Net change in the fair value of forward sales contracts	2,463	(2,870)	(5,451)
Total mortgage production revenue	42,720	31,690	38,498
Servicing revenue	64,821	66,097	66,221
Total mortgage banking revenue	$ 107,541	$ 97,787	$ 104,719