Debt with Commercial Bank (Narrative) (Details) - USD ($) $ in Thousands		6 Months Ended
	Aug. 05, 2014	Jun. 30, 2015	Jun. 30, 2014	Feb. 03, 2015	Apr. 26, 2012
Line of Credit Facility [Line Items]
Document Period End Date		Jun. 30, 2015
Principal payments of debt obligations		$ (623)	$ (321)
Secured Syndicated Credit Facility [Member] | Regions Bank [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 150,000
Deferred Costs, Credit Card Origination Costs, Amount		1,400
Secured Syndicated Credit Facility [Member] | Citi Bank [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount					$ 100,000
Secured Syndicated Credit Facility [Member] | Revolving Credit Facility [Member] | Regions Bank [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Term	5 years
Credit agreement, maximum borrowing capacity	$ 200,000
Line of Credit Facility, Expansion	50,000
Credit agreement, amount outstanding		150,465
Principal payments of debt obligations		$ 0
Secured Syndicated Credit Facility [Member] | Revolving Credit Facility [Member] | Citi Bank [Member]
Line of Credit Facility [Line Items]
Line of credit, interest rate at period end		1.94%
Credit agreement, average amount outstanding during period		$ 133,500
Credit agreement, maximum amount outstanding during period		$ 150,500
Secured Syndicated Credit Facility, First Amendment [Member] | Regions Bank [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount	150,000			$ 190,000
Line of Credit, Accordion				50,000
Line of Credit Facility, Expansion				90,000
Secured Syndicated Credit Facility, First Amendment [Member] | Revolving Credit Facility [Member] | Regions Bank [Member]
Line of Credit Facility [Line Items]
Credit agreement, maximum borrowing capacity	$ 200,000			$ 240,000
Minimum [Member] | Secured Syndicated Credit Facility [Member] | Regions Bank [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	1.50%
Maximum [Member] | Secured Syndicated Credit Facility [Member] | Regions Bank [Member]
Line of Credit Facility [Line Items]
Basis spread on variable interest rate	2.25%