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, 2011	Dec. 31, 2010
SVB Financial Group
Total risk-based capital, actual ratio	13.95%	17.35%
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	$ 1,651,545	$ 1,632,469
Total risk-based capital, well capitalized minimum amount	1,183,790	940,668
Total risk-based capital, adequately capitalized minimum amount	947,032	752,534
Tier 1 risk-based capital, actual ratio	12.62%	13.63%
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	1,493,823	1,282,417
Tier 1 risk-based capital, well capitalized minimum amount	710,274	564,401
Tier 1 risk-based capital, adequately capitalized minimum amount	473,516	376,267
Tier 1 leverage, actual ratio	7.92%	7.96%
Tier 1 leverage, adequately capitalized minimum ratio	4.00%	4.00%
Tier 1 leverage, actual amount	1,493,823	1,282,417
Tier 1 leverage, adequately capitalized minimum amount	754,516	644,041
Silicon Valley Bank
Total risk-based capital, actual ratio	12.33%	15.48%
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	1,414,138	1,400,255
Total risk-based capital, well capitalized minimum amount	1,146,740	904,791
Total risk-based capital, adequately capitalized minimum amount	917,392	723,832
Tier 1 risk-based capital, actual ratio	10.96%	11.61%
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	1,257,030	1,050,745
Tier 1 risk-based capital, well capitalized minimum amount	688,044	542,874
Tier 1 risk-based capital, adequately capitalized minimum amount	458,696	361,916
Tier 1 leverage, actual ratio	6.87%	6.82%
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	1,257,030	1,050,745
Tier 1 leverage, well capitalized minimum amount	915,095	769,990
Tier 1 leverage, adequately capitalized minimum amount	$ 732,076	$ 615,992