Cash and Cash Equivalents - Securities Purchased Under Agreements (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Cash and Cash Equivalents [Abstract]
Average securities purchased under agreements to resell	$ 166,205	$ 132,938
Maximum amount outstanding at any month-end during the year	$ 613,247	$ 375,180

Securities Purchased Under Agreement to Resell, Maximum Month End Balance During Period

No definition available.

Name:	sivb_SecuritiesPurchasedUnderAgreementToResellMaximumMonthEndBalanceDuringPeriod
Namespace Prefix:	sivb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration