Mortgage Banking Activities, Mortgage Banking Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Mortgage Banking Revenue [Abstract]
Net realized gains on sales of mortgage loans	$ 36,379	$ 45,128	$ 68,947
Net change in unrealized gain on mortgage loans held for sale	(674)	2,031	(5,311)
Net change in fair value of mortgage loan commitments	(1,145)	(3,210)	1,599
Net change in the fair value of forward sales contracts	(2,870)	(5,451)	4,393
Total mortgage Production Revenue	31,690	38,498	69,628
Mortgage Servicing Fees	66,097	66,221	64,286
Mortgage banking revenue	$ 97,787	$ 104,719	$ 133,914