Investments and Fair Value Measurements (Details) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended		55 Months Ended
	Nov. 09, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 days	Sep. 30, 2011	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities
Basis of Tested Impact on Securities		0.50%		0.50%		0.50%
Held-to-maturity Securities		$ 1,300,000		$ 1,300,000		$ 1,300,000	$ 1,300,000
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis [Abstract]
Available-for-sale Securities, Debt Maturities, within One Year, Fair Value		0		0		0
Available-for-sale Securities, Debt Maturities, within One Year, Amortized Cost Basis		0		0		0
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Fair Value		0		0		0
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Amortized Cost Basis		0		0		0
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Fair Value		0		0		0
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Amortized Cost Basis		0		0		0
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value		21,041,000		21,041,000		21,041,000
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis		22,325,000		22,325,000		22,325,000
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	21,041,000			50,569,000	88,694,000
Settlements				(31,325,000)	(24,225,000)
Purchases				0	0
Issuances				0	0
Sales				0	0
Transfers in to (out of) Level 3				0	0
Total gains or losses (realized/unrealized) included in earnings				0	0
Total gains or losses (realized/unrealized) included in other comprehensive loss, net of tax				1,797,000	0
Fair value, end of period		21,041,000	64,469,000	21,041,000	64,469,000	21,041,000
Auction Rate Securities, Debt, Rate Setting Interval (in days)				35
Percent of portfolio with AAA credit rating		37.00%		37.00%		37.00%
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		(1,300,000)		(1,300,000)		(1,300,000)
Other comprehensive income		0	0	1,797,000	0
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds		0	0	0	0
Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities	75,000			31,300,000		176,100,000
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investment Inputs Average Life of Underlying Loans		2		2		2	2
Investment Inputs Rate of Return		0.38%		0.38%		0.38%	0.68%
Investment Inputs Discount Rate		0.24%		0.24%		0.24%	0.48%
Investment Inputs Liquidity Discount Rate		0.20%		0.20%		0.20%	0.55%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investment Inputs Average Life of Underlying Loans		12		12		12	12
Investment Inputs Rate of Return		1.97%		1.97%		1.97%	2.92%
Investment Inputs Discount Rate		0.79%		0.79%		0.79%	1.14%
Investment Inputs Liquidity Discount Rate		0.70%		0.70%		0.70%	1.16%
Available-for-sale Securities [Member]
Amortized Cost and Fair Value of Investments
Amortized Cost		22,325,000		22,325,000		22,325,000
Fair Value		21,041,000		21,041,000		21,041,000
Auction rate student loan educational bonds long-term
Amortized Cost and Fair Value of Investments
Amortized Cost		22,325,000		22,325,000		22,325,000	53,650,000
Gross Unrealized Gains		0		0		0	0
Gross Unrealized Losses		1,284,000		1,284,000		1,284,000	3,081,000
Fair Value		$ 21,041,000		$ 21,041,000		$ 21,041,000	$ 50,569,000