FAIR VALUE MEASUREMENTS (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
FAIR VALUE MEASUREMENTS
Higher maturity term	60 days
Maximum number of period for which derivative is outstanding	1
Derivative assets and liabilities, net
Roll forward of derivative instruments which require valuations based upon significant unobservable inputs
Balance at the beginning of the period	$ 20,391	$ 5,415
Settlements	(58,951)	(15,715)
Realized gains recorded in earnings	38,560	10,300
Unrealized gains recorded in earnings	4,370	9,502
Balance at the end of the period	$ 4,370	$ 9,502

- Definition

High end period remaining until maturity for the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeHigherRemainingMaturityRange1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FairValueDisclosuresAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the maximum number of period for which derivative is outstanding.

+ References

No definition available.

+ Details

Name:	wd_DerivativeRemainingMaturityPeriodNumberMaximum
Namespace Prefix:	wd_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	wd_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward
Namespace Prefix:	wd_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of realized gain (loss) recognized in earnings, arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (level 3).

+ References

No definition available.

+ Details

Name:	wd_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilityRealizedGainLossIncludedInEarnings
Namespace Prefix:	wd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the settlements that have taken place during the period in relation to assets and liabilities measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

No definition available.

+ Details

Name:	wd_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitySettlements
Namespace Prefix:	wd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of unrealized gain (loss) recognized in earnings, arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (level 3).

+ References

No definition available.

+ Details

Name:	wd_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilityUnrealizedGainLossIncludedInEarnings
Namespace Prefix:	wd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents assets and liabilities measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

No definition available.

+ Details

Name:	wd_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilityValue
Namespace Prefix:	wd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant