Regulatory Matters 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	Dec. 31, 2016	Dec. 31, 2015
SVB Financial Group
CET 1 risk-based capital, actual ratio	12.80%	12.28%
CET 1 risk-based capital, well capitalized minimum ratio	6.50%	6.50%
CET 1 risk-based capital, adequately capitalized minimum ratio	4.50%	4.50%
CET 1 risk-based capital, actual amount	$ 3,616,404	$ 3,183,206
CET 1 risk-based capital, well capitalized minimum amount	1,836,169	1,684,774
CET 1 risk-based capital, adequately capitalized minimum amount	$ 1,271,194	$ 1,166,382
Tier 1 risk-based capital, actual ratio	13.26%	12.83%
Tier 1 risk-based capital, well capitalized minimum ratio	8.00%	8.00%
Tier 1 risk-based capital, adequately capitalized minimum ratio	6.00%	6.00%
Tier 1 risk-based capital, actual amount	$ 3,744,605	$ 3,325,245
Tier 1 risk-based capital, well capitalized minimum amount	2,259,900	2,073,567
Tier 1 risk-based capital, adequately capitalized minimum amount	$ 1,694,925	$ 1,555,176
Total risk-based capital, actual ratio	14.21%	13.84%
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	$ 4,015,236	$ 3,586,466
Total risk-based capital, well capitalized minimum amount	2,824,875	2,591,959
Total risk-based capital, adequately capitalized minimum amount	$ 2,259,900	$ 2,073,567
Tier 1 leverage, actual ratio	8.34%	7.63%
Tier 1 leverage, adequately capitalized minimum ratio	4.00%	4.00%
Tier 1 leverage, actual amount	$ 3,744,605	$ 3,325,245
Tier 1 leverage, adequately capitalized minimum amount	$ 1,796,387	$ 1,743,555
Silicon Valley Bank
CET 1 risk-based capital, actual ratio	12.65%	12.52%
CET 1 risk-based capital, well capitalized minimum ratio	6.50%	650.00%
CET 1 risk-based capital, adequately capitalized minimum ratio	4.50%	450.00%
CET 1 risk-based capital, actual amount	$ 3,397,232	$ 3,043,435
CET 1 risk-based capital, well capitalized minimum amount	1,745,695	1,579,568
CET 1 risk-based capital, adequately capitalized minimum amount	$ 1,208,558	$ 1,093,547
Tier 1 risk-based capital, actual ratio	12.65%	12.52%
Tier 1 risk-based capital, well capitalized minimum ratio	8.00%	8.00%
Tier 1 risk-based capital, adequately capitalized minimum ratio	6.00%	6.00%
Tier 1 risk-based capital, actual amount	$ 3,397,232	$ 3,043,435
Tier 1 risk-based capital, well capitalized minimum amount	2,148,548	1,944,083
Tier 1 risk-based capital, adequately capitalized minimum amount	$ 1,611,411	$ 1,458,063
Total risk-based capital, actual ratio	13.66%	13.60%
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	$ 3,667,709	$ 3,304,537
Total risk-based capital, well capitalized minimum amount	2,685,685	2,430,104
Total risk-based capital, adequately capitalized minimum amount	$ 2,148,548	$ 1,944,083
Tier 1 leverage, actual ratio	7.67%	7.09%
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	$ 3,397,232	$ 3,043,435
Tier 1 leverage, well capitalized minimum amount	2,214,467	2,147,532
Tier 1 leverage, adequately capitalized minimum amount	$ 1,771,574	$ 1,718,026