Loans and Allowance for Loan Losses Activity in Allowance for Unfunded Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Activity in Allowance for Unfunded Commitments [Abstract]
Reserve For Unfunded Credit Commitments	$ 51,770	$ 45,265	$ 34,415	$ 36,419
Provision For Unfunded Credit Commitments	6,365	10,982	(1,946)
Foreign Currency Translation, Unfunded Credit Commitments	$ 140	$ (132)	$ (58)

Amount of gain (loss) from converting allowance reserve for unfunded credit commitments to currency of reporting entity from amount denominated or measured in a different currency which decreases (increases) the allowance for unfunded credit commitments.

No definition available.

Name:	sivb_ForeignCurrencyTranslationUnfundedCreditCommitments
Namespace Prefix:	sivb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration