| **Transfer Between Levels 1, 2 and 3 and Reasons For Those Transfers (Detail) (USD $)In Thousands, unless otherwise specified** | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                            |
|---------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| Significant Other Observable Inputs (Level 2)                                                                                   |                                                                                                                                                                                                                                                                                                                                                                      |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                |                                                                                                                                                                                                                                                                                                                                                                      |
| Transfer between Levels 1, 2 and 3                                                                                              | $ 12,205                                                                                                                                                                                                                                                                                                                                                                  |
| Reason for Transfer                                                                                                             | The interest rate swap and cap instruments were transferred from Level 3 to Level 2 as of March 31, 2012 due to the availability of additional valuation information. These instruments are valued using widely accepted valuation techniques including discounted cash flow analysis using observable inputs such as contractual terms and LIBOR-based rate curves. |
| Significant Other Observable Inputs (Level 2) | Interest Rate Swap Assets                                                       |                                                                                                                                                                                                                                                                                                                                                                      |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                |                                                                                                                                                                                                                                                                                                                                                                      |
| Transfer between Levels 1, 2 and 3                                                                                              | 4,862                                                                                                                                                                                                                                                                                                                                                                     |
| Significant Other Observable Inputs (Level 2) | Interest Rate Cap                                                               |                                                                                                                                                                                                                                                                                                                                                                      |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                |                                                                                                                                                                                                                                                                                                                                                                      |
| Transfer between Levels 1, 2 and 3                                                                                              | 409                                                                                                                                                                                                                                                                                                                                                                       |
| Significant Other Observable Inputs (Level 2) | Interest Rate Swap Liabilities                                                  |                                                                                                                                                                                                                                                                                                                                                                      |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                |                                                                                                                                                                                                                                                                                                                                                                      |
| Transfer between Levels 1, 2 and 3                                                                                              | 6,934                                                                                                                                                                                                                                                                                                                                                                     |
| Significant Unobservable Inputs (Level 3)                                                                                       |                                                                                                                                                                                                                                                                                                                                                                      |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                |                                                                                                                                                                                                                                                                                                                                                                      |
| Transfer between Levels 1, 2 and 3                                                                                              | (12,205)                                                                                                                                                                                                                                                                                                                                                                  |
| Significant Unobservable Inputs (Level 3) | Interest Rate Swap Assets                                                           |                                                                                                                                                                                                                                                                                                                                                                      |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                |                                                                                                                                                                                                                                                                                                                                                                      |
| Transfer between Levels 1, 2 and 3                                                                                              | (4,862)                                                                                                                                                                                                                                                                                                                                                                   |
| Significant Unobservable Inputs (Level 3) | Interest Rate Cap                                                                   |                                                                                                                                                                                                                                                                                                                                                                      |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                |                                                                                                                                                                                                                                                                                                                                                                      |
| Transfer between Levels 1, 2 and 3                                                                                              | (409)                                                                                                                                                                                                                                                                                                                                                                     |
| Significant Unobservable Inputs (Level 3) | Interest Rate Swap Liabilities                                                      |                                                                                                                                                                                                                                                                                                                                                                      |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                |                                                                                                                                                                                                                                                                                                                                                                      |
| Transfer between Levels 1, 2 and 3                                                                                              | $ (6,934)                                                                                                                                                                                                                                                                                                                                                                 |

| X                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Disclosures concerning the reasons for transfers out of Level 3 of the fair value hierarchy.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258
+ Details**Name:**us-gaap_FairValueLevel3TransfersOutDescription**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This element represents [net] transfers in to and out of assets measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -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.
+ Details**Name:**us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |