Capital Ratios for Company and Bank under Federal Regulatory Guidelines, Compared to Minimum Regulatory Capital Requirements for Adequately Capitalized and Well Capitalized Depository Institution (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
SVB Financial Group
Total risk-based capital, actual ratio	14.05%	13.95%
Total risk-based capital, well capitalized minimum ratio	10.00%	10.00%
Total risk-based capital, adequately capitalized minimum ratio	8.00%	8.00%
Total risk-based capital, actual amount	$ 1,901,672	$ 1,651,545
Total risk-based capital, well capitalized minimum amount	1,353,298	1,183,790
Total risk-based capital, adequately capitalized minimum amount	1,082,639	947,032
Tier 1 risk-based capital, actual ratio	12.79%	12.62%
Tier 1 risk-based capital, well capitalized minimum ratio	6.00%	6.00%
Tier 1 risk-based capital, adequately capitalized minimum ratio	4.00%	4.00%
Tier 1 risk-based capital, actual amount	1,730,866	1,493,823
Tier 1 risk-based capital, well capitalized minimum amount	811,979	710,274
Tier 1 risk-based capital, adequately capitalized minimum amount	541,319	473,516
Tier 1 leverage, actual ratio	8.06%	7.92%
Tier 1 leverage, adequately capitalized minimum ratio	4.00%	4.00%
Tier 1 leverage, actual amount	1,730,866	1,493,823
Tier 1 leverage, adequately capitalized minimum amount	859,057	754,516
Silicon Valley Bank
Total risk-based capital, actual ratio	12.53%	12.33%
Total risk-based capital, well capitalized minimum ratio	10.00%	10.00%
Total risk-based capital, adequately capitalized minimum ratio	8.00%	8.00%
Total risk-based capital, actual amount	1,650,732	1,414,138
Total risk-based capital, well capitalized minimum amount	1,317,789	1,146,740
Total risk-based capital, adequately capitalized minimum amount	1,054,231	917,392
Tier 1 risk-based capital, actual ratio	11.24%	10.96%
Tier 1 risk-based capital, well capitalized minimum ratio	6.00%	6.00%
Tier 1 risk-based capital, adequately capitalized minimum ratio	4.00%	4.00%
Tier 1 risk-based capital, actual amount	1,481,571	1,257,030
Tier 1 risk-based capital, well capitalized minimum amount	790,673	688,044
Tier 1 risk-based capital, adequately capitalized minimum amount	527,115	458,696
Tier 1 leverage, actual ratio	7.06%	6.87%
Tier 1 leverage, well capitalized minimum ratio	5.00%	5.00%
Tier 1 leverage, adequately capitalized minimum ratio	4.00%	4.00%
Tier 1 leverage, actual amount	1,481,571	1,257,030
Tier 1 leverage, well capitalized minimum amount	1,049,750	915,095
Tier 1 leverage, adequately capitalized minimum amount	$ 839,800	$ 732,076