Summary of Significant Accounting Policies (Details Textual) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2011 Instrument Acre	Jun. 30, 2010 Instrument	Dec. 31, 2010 Instrument	Jun. 30, 2009 Instrument
Derivative Contract Details (Textual) [Abstract]
Inception date of derivative agreements	Apr. 01, 2009
Maturity date of derivative agreements	Apr. 30, 2014
Summary of Significant Accounting Policies (Textual) [Abstract]
Number of derivative instruments held	2	2	2	2
Loss on derivatives included as a component of other comprehensive income, net of taxes	$ 1	$ 354
Interest expense on derivatives related to credit risk	11
Amount agreed to pay to settle the qui tam matter as restricted cash	0		5,200
Pledged collateral as noncurrent restricted cash	555		760
Reclassified gains or losses on derivative instruments from accumulated other comprehensive (loss) income into earnings	0
Reduced pledge collateral	555
Average days from the date of receipt in which funds remain as restricted cash and cash equivalents	60 to 90 Days
Area of the Company's campus in Phoenix, Arizona	110
Reduction in revenue due to scholarships offered to students	34,939	25,043
Collaboration agreement cost			8,500
Arrangement expense	403	4,975
Due to related party	67		9,367
Segment reporting operating income or expense		0
Interest Rate Corridor [Member]
Derivative Contract Details (Textual) [Abstract]
Inception date of derivative agreements	Jul. 01, 2009
Maturity date of derivative agreements	Apr. 30, 2014
Notional amount of interest rate swap	11,055
Fair value of interest rate corridor included in other assets	10		27
Interest rate payable on interest rate corridor if 30 Day LIBOR is less than 4%	30 Day LIBOR	30 Day LIBOR	30 Day LIBOR
Interest rate payable on interest rate corridor 30 Day LIBOR equal to 4% through 6%	4.00%	4.00%	4.00%
Interest rate payable on interest rate corridor 30 Day LIBOR exceeds 6%	30 Day LIBOR less 2%	30 Day LIBOR less 2%	30 Day LIBOR less 2%
Interest Rate Swap [Member]
Derivative Contract Details (Textual) [Abstract]
Inception date of derivative agreements	May 01, 2010
Maturity date of derivative agreements	Apr. 30, 2014
Notional amount of interest rate swap	11,055
Interest rate receivable on interest rate swap amortizing notional amount	30 Day LIBOR	30 Day LIBOR	30 Day LIBOR
Fixed Interest rate payable on interest rate swap amortizing notional amount	3.245%	3.245%	3.245%
Fair value of interest rate swap is a liability ,which is included in other non current liability	$ 659		$ 686