Mortgage Banking Activities Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Mortgage Banking Revenue [Abstract]
Net realized gains on sale of mortgage loans	$ 12,041	$ 23,110	$ 32,443	$ 47,424
Net change in unrealized gain on mortgage loans held for sale	(1,492)	(2,518)	3,335	4,649
Net change in the fair value of mortgage loan commitments	(1,927)	(6,901)	(667)	10,464
Net change in the fair value of forward sales contracts	(293)	8,267	(4,399)	(4,846)
Total production revenue	8,329	21,958	30,712	57,691
Servicing revenue	16,561	16,558	49,645	47,809
Total mortgage banking revenue	$ 24,890	$ 38,516	$ 80,357	$ 105,500