Capital limitation percentage.

No definition available.

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- Definition

Extension period for federal reserve board for bank holding.

+ References

No definition available.

+ Details

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- Details

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- Definition

Junior subordinated debentures issued.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Tier 2 risk based capital to risk weighted assets.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Amount of cash eligible for distribution to members or limited partners of limited liability company (LLC) or limited partnership (LP), subject to reserves to be maintained as defined in operating or partnership agreement, or in a credit facility agreement.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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- Definition

The amount of excess Tier 1 Risk Based Capital (which consists of the types of financial capital considered the most reliable and liquid, primarily Shareholders' equity. Examples of Tier 1 capital are common stock or unit, preferred stock or unit that is irredeemable and noncumulative, and retained earnings) divided by risk-weighted assets which are assets that are weighted for credit risk according to a formula used by the Reserve Bank.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

+ Details

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- Definition

Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, and (3) securities available-for-sale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.4)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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- Definition

Tier 1 capital divided by risk weighted assets as defined by regulations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1H

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 505

-Section 50

-Paragraph 1

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

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Junior Subordinated Debentures Held by Trusts that Issued Capital Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	0 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Mar. 16, 2009
Junior Subordinated Debentures Held By Trusts That Issued Capital Debt [Abstract]
Junior subordinated debentures issued		$ 92.8snbc_JuniorSubordinatedDebenturesIssued	$ 92.8snbc_JuniorSubordinatedDebenturesIssued
Common capital securities		2.8us-gaap_MarketableSecurities
Extension period of bank holding		2 years
Tier 1 capital limitation, interest		25.00%
Limited capital securities and other restricted core capital elements, net of goodwill		25.00%snbc_CapitalLimitationPercentage
Tier 1 capital elements		16.12%		25.00%
Tier 2 capital elements				25.00%
Junior subordinated debentures interest rate description		The three-month LIBOR rate at December 31, 2014 was 0.26%.
Junior subordinated debentures interest rate	0.26%
Cash balance available to pay junior subordinated debenture interest obligations		$ 29.8us-gaap_CashAvailableForDistributions