Regulatory Requirements (Net Capital and Net Capital Requirements for CS&Co) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Banking and Thrift [Abstract]
Net capital	$ 2,118,000	$ 1,846,000
Minimum net capital required	250	250
2% of Aggregate Debit Balances	435,000	355,000
Net capital in excess of required net capital	$ 1,683,000	$ 1,491,000

The amount of net capital in excess of the alternative minimum required net capital.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

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- References

No definition available.

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- Definition

Amount of minimum net capital required to be maintained to engage in securities transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

+ Details

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- Definition

Net capital is equal to the net worth of the broker dealer, less certain items such as exchange memberships, carrying value of securities not readily marketable, haircuts on marketable securities in proprietary accounts, furniture and equipment and other illiquid assets as defined.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

+ Details

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- Definition

This element represents the amount of net capital of a broker or dealer that has elected not to be subject to the Aggregate Indebtedness Standard (as defined). The amount of net capital represented by this element is the greater of $250,000 or two percent of aggregate debit items computed in accordance with the Formula for Determination of Reserve Requirements for Brokers and Dealers (as defined).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

+ Details

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