Commitments and Contingencies (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($) properties	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) properties	Jun. 30, 2016 USD ($)	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Number of non-cancelable operating leases | properties	248		248
Rent expense	$ 9,500	$ 9,500	$ 19,200	$ 19,200
Rent income	494	502	1,000	1,000
Standby letters of credit that expire within one year	53,900		53,900
Standby letters of credit that expire thereafter	19,000		19,000
Standby letters of credit, fees	310	$ 262	464	$ 372
Residential mortgage loan repurchase reserve liability	$ 1,100		1,100
Days past due of GNMA loans available for repurchase	90 days
GNMA Loans past due by 90 days, but not yet repurchased	$ 16,300		$ 16,300
Real Estate Loans As Part Of Loan Portfolio
Concentration Risk [Line Items]
Concentration risk, percentage			75.00%		76.00%