Long-Term Debt (Details) (Line of Credit [Member], Wells Fargo Credit Agreement [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	125
Line of Credit Facility, Amount Outstanding	52.5
Line of Credit Facility, Remaining Borrowing Capacity	72.5
Fixed 30 Day Interest Rate 1 [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	50.5
Debt Instrument, Interest Rate, Stated Percentage	1.50%
Swingline Variable Interest Rate [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	2.0
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.72%
Borrower's Option 1 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	base rate
Debt Instrument, Basis Spread on Variable Rate	0.25%
Borrower's Option 2 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	London Inter-Bank Offered Rate (“LIBOR”) Market Index Rate
Debt Instrument, Basis Spread on Variable Rate	1.25%
Borrower's Option 3 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	LIBOR Rate
Debt Instrument, Basis Spread on Variable Rate	1.25%
Default Option [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	LIBOR Market Index Rate
Debt Instrument, Basis Spread on Variable Rate	1.25%
Base Rate Option 1 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	prime rate (as announced by Wells Fargo)
Base Rate Option 2 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	federal funds rate
Debt Instrument, Basis Spread on Variable Rate	0.50%
Base Rate Option 3 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	LIBOR for an interest period of one month
Debt Instrument, Basis Spread on Variable Rate	1.00%