Mortgage Banking Activities Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Mortgage Banking Revenue [Abstract]
Net realized gains on sale of mortgage loans	$ 10,718	$ 11,787	$ 19,636	$ 20,402
Net change in unrealized gain on mortgage loans held for sale	1,047	985	(322)	4,827
Net change in the fair value of mortgage loan commitments	(1,124)	(3,274)	950	1,260
Net change in the fair value of forward sales contracts	(726)	4,342	(897)	(4,106)
Total production revenue	9,915	13,840	19,367	22,383
Servicing revenue	16,431	16,436	33,004	33,084
Total mortgage banking revenue	$ 26,346	$ 30,276	$ 52,371	$ 55,467