|
Related Party Transactions Deferred Fee Liability to Related Party (Details) (USD $)
In Thousands, except Share data, unless otherwise specified |
0 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
|
Jul. 15, 2009
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2010
|
|
| Related Party Transaction [Line Items] | ||||
| Increase (decrease) in deferred fee liability to related party | $ 11,448 | $ (6,107) | $ 6,268 | |
|
WGL Capital Corp
|
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| Related Party Transaction [Line Items] | ||||
| Deferred fee liability to related party, amount assumed | 51,594 | |||
| Consideration received, in cash | 4,487 | |||
| Consideration received, in common units (in shares) | 2,725,533 | |||
| Consideration received, share price per common unit (in dollars per share) | $ 17.28 | |||
| Increase (decrease) in deferred fee liability to related party | 11,448 | 6,107 | 6,268 | |
| Deferred fee liability | $ 0 | $ 58,747 | ||