Parent Company Only Condensed Financial Information Condensed Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Adjustments to reconcile net income to net cash used for operating activities:
Gains on derivative instruments, net	$ (96,845)	$ (42,184)	$ (18,679)
Gains on investment securities, net	(267,023)	(419,408)	(122,114)
Amortization of share-based compensation	29,545	25,413	21,861
Impairment loss on SVBIF Sale Transaction	13,934	0	0
Other, net	20,044	(22,684)	15,143
Net cash used for operating activities	255,517	171,778	196,108
Cash flows from investing activities:
Net (increase) decrease in loans	(3,480,531)	(1,943,650)	(1,964,250)
Net cash used for investing activities	(12,233,931)	(2,838,988)	(2,886,368)
Cash flows from financing activities:
Principal payments of other long term debt	0	0	(1,222)
Tax benefit from stock exercises	9,602	6,826	5,581
Proceeds from issuance of common stock and ESPP	22,146	46,569	29,282
Net proceeds from public equity offering	434,866	0	0
Net cash provided by financing activities	12,250,649	3,197,006	2,584,295
Net increase (decrease) in cash and cash equivalents	272,235	529,796	(105,965)
Cash and cash equivalents at beginning of period	1,538,779	1,008,983	1,114,948
Cash and cash equivalents at end of period	1,796,062	1,538,779	1,008,983
Parent Company
Cash flows from operating activities:
Net income attributable to SVBFG	263,925	215,853	175,103
Adjustments to reconcile net income to net cash used for operating activities:
Gains on derivative instruments, net	(66,604)	(47,421)	(17,289)
Gains on investment securities, net	(8,750)	(15,238)	(15,329)
Net income of subsidiaries	22,489	18,417	41,749
Cash dividends from bank subsidiary	0	10,000	0
Amortization of share-based compensation	29,545	25,413	21,861
Decrease (increase) in other assets	44,006	(11,901)	5,463
Increase (decrease) in other liabilities	28,303	1,506	3,952
Impairment loss on SVBIF Sale Transaction	9,564	0	0
Other, net	584	(1,269)	2,273
Net cash used for operating activities	14,159	(67,327)	(40,818)
Cash flows from investing activities:
Net decrease in investment securities from purchases, sales and maturities	15,469	70,479	11,833
Net (increase) decrease in loans	(11,893)	4,078	2,034
Net cash used for investing activities	(384,514)	63,013	39,059
Cash flows from financing activities:
Principal payments of other long term debt	0	0	(1,222)
Tax benefit from stock exercises	9,431	6,826	5,581
Proceeds from issuance of common stock and ESPP	22,146	46,569	29,282
Net proceeds from public equity offering	434,866	0	0
Net cash provided by financing activities	466,443	53,395	33,641
Net increase (decrease) in cash and cash equivalents	96,088	49,081	31,882
Cash and cash equivalents at beginning of period	218,148	169,067	137,185
Cash and cash equivalents at end of period	314,236	218,148	169,067
Parent Company | Bank Subsidiaries
Adjustments to reconcile net income to net cash used for operating activities:
Net income of subsidiaries	(249,405)	(186,195)	(195,395)
Cash flows from investing activities:
Investment in subsidiaries	(432,804)	(21,469)	12,180
Parent Company | Nonbank Subsidiaries
Adjustments to reconcile net income to net cash used for operating activities:
Net income of subsidiaries	(37,009)	(58,075)	(21,457)
Cash flows from investing activities:
Investment in subsidiaries	$ 44,714	$ 9,925	$ 13,012