Debt with Commercial Bank (Narrative) (Details) - USD ($)		3 Months Ended
	Aug. 05, 2014	Mar. 31, 2016	Mar. 31, 2015	Oct. 14, 2015	Feb. 03, 2015	Apr. 26, 2012
Line of Credit Facility [Line Items]
Document Period End Date		Mar. 31, 2016
Proceeds from Lines of Credit		$ 20,000,000	$ 15,000,000
Principal payments of debt obligations		0	$ (12,000)
Secured Syndicated Credit Facility [Member] | Regions Bank [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 150,000,000
Deferred Costs, Credit Card Origination Costs, Amount		1,500,000
Secured Syndicated Credit Facility [Member] | Citi Bank [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount						$ 100,000,000
Secured Syndicated Credit Facility [Member] | Revolving Credit Facility [Member] | Regions Bank [Member]
Line of Credit Facility [Line Items]
Line of Credit, Accordion				$ 50,000,000
Debt Instrument, Term	5 years
Credit agreement, maximum borrowing capacity	$ 200,000,000
Line of Credit Facility, Expansion	50,000,000
Credit agreement, amount outstanding		226,465,000
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		2.50%
Credit agreement, average amount outstanding during period		$ 209,800,000
Credit agreement, maximum amount outstanding during period		$ 226,500,000
Secured Syndicated Credit Facility, First Amendment [Member] | Regions Bank [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount	150,000,000				$ 190,000,000
Line of Credit, Accordion					50,000,000
Line of Credit Facility, Expansion					90,000,000
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	$ 200,000,000			240,000,000	$ 240,000,000
Secured Syndicated Credit Facility, First Amendment [Member] | Revolving Credit Facility [Member] | TD Bank [Member]
Line of Credit Facility [Line Items]
Credit agreement, maximum borrowing capacity				$ 25,000,000
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%