Commitments and Contingencies (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Loss Contingencies [Line Items]
Rent expense	$ 2,619	$ 2,537	$ 3,163
Sublease income	304	68	1,220
Guarantee liability		1,084
Principal transactions and other income	(7,232)	(2,439)	1,881
Potential liability, assuming the restricted stock or restricted units to vest	68
Guarantee Obligations [Member]
Loss Contingencies [Line Items]
Guarantee liability		1,084
Principal transactions and other income	$ 1,084

Potential liability assuming the restricted stock or restricted units to vest .

No definition available.

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- Definition

Principal transactions include all gains, losses, and income (interest and dividend) from securities or loans classified as other investments, at fair value (including gains and losses on derivatives classified as other investments, at fair value) in the consolidated balance sheets. Other income includes foreign currency gains and losses, interest earned on cash and cash equivalents, and other miscellaneous income.

+ References

No definition available.

+ Details

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- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

+ Details

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- Details

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- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

+ Details

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Period Type:	duration

- Definition

The total amount of sublease rental income recognized during the period that reduces the entity's rent expense incurred under operating leases.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

+ Details

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