Derivative Instruments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Derivative Instruments [Line Items]
Period of LIBOR interest rate	30 days
Fair value of interest rate corridor instrument	$ 0	$ 1
Effective portion of gain/loss on derivatives included as a component of other comprehensive income, net of taxes		92
Notional amount of interest rate swap	9,771
Maximum percentage of variable interest rates based on LIBOR	4.00%
Percentage of amount paid by University	4.00%
Minimum percentage of LIBOR	4.00%
Maximum percentage of LIBOR	6.00%
Percentage deducted from LIBOR for actual payment	2.00%
Interest expense on derivatives related to credit risk	3
Cash Flow Hedging [Member]
Derivative Instruments [Line Items]
Effective portion of gain/loss on derivatives included as a component of other comprehensive income, net of taxes	241	10	551
Interest Rate Swap [Member]
Derivative Instruments [Line Items]
Fair value of the interest rate swap liability, included in other noncurrent liabilities	390	629
Notional amount of interest rate swap	9,771
Percentage of fixed interest on the amortizing notional amount of interest rate swap	3.245%
Interest rate swap reflected in a restricted cash account	$ 225	$ 555

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Interest expense on derivatives related to credit risk.

+ References

No definition available.

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- Definition

Maximum percentage of variable interest rates based on base interest rate.

+ References

No definition available.

+ Details

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- Definition

Percentage deducted from base interest rate for actual payment.

+ References

No definition available.

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- Definition

Percentage of amount paid by University.

+ References

No definition available.

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- Definition

Percentage of fixed interest on the amortizing notional amount.

+ References

No definition available.

+ Details

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- Definition

Period of base interest rate.

+ References

No definition available.

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- Definition

Reduced pledge collateral.

+ References

No definition available.

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- Definition

Fair value as of the balance sheet date of credit risk derivative assets, which includes all such derivative instruments in hedging and non-hedging relationships that are recognized as assets on the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13433-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 17

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Fair value as of the balance sheet date of credit risk derivative liabilities, which includes all such derivative instruments in hedging and non-hedging relationships that are recognized as liabilities on the balance sheet.

+ References

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- Definition

High end of the range of variable interest rates when a range is presented for a group of interest rate derivatives.

+ References

No definition available.

+ Details

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- Definition

Low end of the range of variable interest rates when a range is presented for a group of interest rate derivatives.

+ References

No definition available.

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- Definition

Aggregate notional amount of interest rate derivatives, which relates to the currency amount specified in the interest rate derivative instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

Reference 3: http://www.xbrl.org/2003/role/presentationRef

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- Definition

Net of tax amount of the income statement impact of the reclassification adjustment of accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges realized in net income. Also includes reclassification adjustments of an entity's share of an equity investee's deferred hedging gain (loss) realized in net income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 130

-Paragraph 24

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 38

-Subparagraph c(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 31, 46

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Reclassification Adjustments

-URI http://asc.fasb.org/extlink&oid=6522872

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-Number 130

-Paragraph 18, 19

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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