Investments and Fair Value Measurements (Details) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended		67 Months Ended
	Nov. 07, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Dec. 31, 2012	Feb. 14, 2008
Schedule of Available-for-sale Securities
Basis of Tested Impact on Securities		0.50%		0.50%		0.50%
Held-to-maturity Securities		$ 1,400,000		$ 1,400,000		$ 1,400,000	$ 1,300,000
Amortized Cost and Fair Value of Investments
Amortized Cost		11,425,000		11,425,000		11,425,000		198,500,000
Gross Unrealized Gains		0		0		0
Gross Unrealized Losses		230,000		230,000		230,000
Fair Value		11,195,000		11,195,000		11,195,000
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, within One Year, Fair Value		6,850,000		6,850,000		6,850,000
Available-for-sale Securities, Debt Maturities, within One Year, Amortized Cost Basis		6,850,000		6,850,000		6,850,000
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		4,345,000		4,345,000		4,345,000
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis		4,575,000		4,575,000		4,575,000
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	11,195,000			20,016,000	50,569,000
Settlements				(9,875,000)	(31,325,000)
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 income, net of tax					1,797,000
Fair value, end of period		11,195,000	21,041,000	11,195,000	21,041,000	11,195,000
Maturity and calls of investments				(9,875,000)	(31,325,000)
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		(200,000)		(200,000)		(200,000)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax		454,000	0	1,054,000	1,797,000
Available-for-sale Securities, Gross Realized Gain (Loss)		0	0	0	0
Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities	6,900,000	100,000		9,875,000	31,325,000	193,900,000
Auction Rate Student Loan Educational Bonds Current [Member]
Amortized Cost and Fair Value of Investments
Amortized Cost		6,850,000		6,850,000		6,850,000
Gross Unrealized Gains		0		0		0
Gross Unrealized Losses		0		0		0
Fair Value		6,850,000		6,850,000		6,850,000
Available-for-sale Securities [Member]
Amortized Cost and Fair Value of Investments
Amortized Cost		11,425,000		11,425,000		11,425,000
Fair Value		11,195,000		11,195,000		11,195,000
Auction rate student loan educational bonds long-term
Amortized Cost and Fair Value of Investments
Amortized Cost		4,575,000		4,575,000		4,575,000	21,300,000
Gross Unrealized Gains		0		0		0	0
Gross Unrealized Losses		230,000		230,000		230,000	1,284,000
Fair Value		$ 4,345,000		$ 4,345,000		$ 4,345,000	$ 20,016,000