Fair Value Measurements - Roll Forward, Level 3 (Details) - Level 3 - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Rollforward for financial instruments measured at fair value using Level 3 inputs
Asset balance, beginning of period	$ 98,154	$ 73,617	$ 91,686	$ 97,769
Purchases/Additions	30,517	14,820	60,796	33,813
Sales/Reductions	(4,614)	(5,685)	(26,430)	(40,607)
Total gains or losses (realized or unrealized):
Included in Net Income	(888)	(3,441)	(2,883)	(11,664)
Asset balance, end of period	123,169	79,311	123,169	79,311
Loans Held for Sale
Rollforward for financial instruments measured at fair value using Level 3 inputs
Asset balance, beginning of period	40,781	30,037	36,972	35,801
Purchases/Additions	19,156	8,881	39,706	25,384
Sales/Reductions	(4,614)	(5,685)	(17,127)	(23,108)
Total gains or losses (realized or unrealized):
Included in Net Income	(958)	(1,688)	(5,186)	(6,532)
Asset balance, end of period	54,365	31,545	54,365	31,545
MSR
Rollforward for financial instruments measured at fair value using Level 3 inputs
Asset balance, beginning of period	57,373	43,580	54,714	61,968
Purchases/Additions	11,361	5,939	21,090	8,429
Sales/Reductions			(9,303)	(17,499)
Total gains or losses (realized or unrealized):
Included in Net Income	70	(1,753)	2,303	(5,132)
Asset balance, end of period	$ 68,804	$ 47,766	$ 68,804	$ 47,766