Basis of Presentation (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Customer deposits		$ 294,548		$ 254,624
Contract asset insurance renewals		31,400
Residential mortgage loans available-for-sale fair value		326,995		461,354
Residential mortgage loans available-for-sale aggregate outstanding principal balance		315,500		444,200
Changes in fair value, gain (loss)		(1,100)	$ (100)
Net gains from the sale of mortgages		$ 24,000	27,000
Variability in future cash flows of derivative instruments in days		60 days
Cumulative effect of accounting change			22,411
Interest rate lock commitments
Finite-Lived Intangible Assets [Line Items]
Derivative, notional amount		$ 356,900		285,000
Forward contracts
Finite-Lived Intangible Assets [Line Items]
Derivative, notional amount		498,000		511,000
Whole loan commitments
Finite-Lived Intangible Assets [Line Items]
Derivative, notional amount		$ 146,400		$ 187,800
Retained Earnings
Finite-Lived Intangible Assets [Line Items]
Cumulative effect of accounting change	$ 22,400		$ 22,411