Commitments and Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($) properties store	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) properties store	Sep. 30, 2016 USD ($)	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Number of non-cancelable operating leases | properties	237		237
Rent expense	$ 9,700	$ 9,800	$ 28,900	$ 29,000
Rent income	529	508	1,500	1,500
Standby letters of credit, financial guarantees required to perform on	0	0	0	0
Standby letters of credit that expire within one year	51,500		51,500
Standby letters of credit that expire thereafter	19,800		19,800
Standby letters of credit, fees	218	$ 235	682	$ 608
Residential mortgage loan repurchase reserve liability	1,200		$ 1,200
Days past due of GNMA loans available for repurchase			90 days
GNMA Loans past due by 90 days, but not yet repurchased	$ 12,300		$ 12,300
Number of stores to be consolidated | store	30		30
Real Estate Loans As Part Of Loan Portfolio
Concentration Risk [Line Items]
Concentration risk, percentage			75.00%		76.00%