Credit Facilities and Long-Term Debt, Revolving Credit Facility (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 250.0
Expiration date	Mar. 31, 2018
Additional available borrowing capacity	$ 161.1
Financial covenants	At any time that our average borrowing availability is less than $25 million, the terms of our restated credit agreement provide for, among other provisions, a financial covenant requiring us, on a consolidated basis, to maintain specified levels of fixed charge coverage at the end of each fiscal quarter (rolling twelve months).
Increase in the amount of cash dividends that we may pay in any twelve month period	$ 5.0
Total cash available for dividends	20.0
Increase the amount of cash that we may utilize to purchase or redeem our common stock in any fiscal year	10.0
Total cash that we may utilize to purchase or redeem our common stock in any fiscal year	20.0
General Electric Capital Corporation Credit Facility [Member]
Line of Credit Facility [Line Items]
Outstanding borrowings under credit facility	$ 52.9		$ 56.6
Weighted average interest rate (in hundredths)	1.80%		1.80%
General Electric Capital Corporation Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Conditions for required financial covenants, maximum borrowing availability	$ 25.0
General Electric Capital Corporation Credit Facility [Member] | Direct Borrowings [Member]
Line of Credit Facility [Line Items]
Outstanding borrowings under credit facility	$ 50.0		$ 53.0
Weighted average interest rate (in hundredths)	1.70%		1.70%
General Electric Capital Corporation Credit Facility [Member] | Index Loan [Member]
Line of Credit Facility [Line Items]
Outstanding borrowings under credit facility	$ 2.9		$ 3.6
Weighted average interest rate (in hundredths)	3.80%		3.80%
Average daily loan balance outstanding	$ 3.9	$ 4.5	$ 4.4
GE Canada Finance Holding Company Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	10.0
Outstanding borrowings under credit facility	$ 0.0