Mortgage Banking Activities Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Mortgage Banking Revenue [Abstract]
Net realized gains on sale of mortgage loans	$ 5,693	$ 8,918
Net change in unrealized gain on mortgage loans held for sale	(53)	(1,369)
Net change in the fair value of mortgage loan commitments	2,713	2,074
Net change in the fair value of forward sales contracts	(485)	(171)
Total production revenue	7,868	9,452
Servicing revenue	15,966	16,573
Total mortgage banking revenue	$ 23,834	$ 26,025