Condensed Statement of Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Interest income	$ 168,168	$ 161,958	$ 159,818	$ 158,774	$ 147,802	$ 143,324	$ 140,161	$ 134,101	$ 648,718	$ 565,388	$ 461,731
Interest expense	(7,605)	(7,528)	(7,884)	(7,837)	(7,732)	(7,869)	(9,708)	(13,802)	(30,854)	(39,111)	(43,596)
Gains on derivative instruments, net									22,120	38,681	9,522
Gains on investment securities, net									122,114	195,034	93,360
Income tax benefit	29,526	28,470	31,517	23,756	26,284	26,770	43,263	22,770	(113,269)	(119,087)	(61,402)
Net income available to common stockholders	50,421	42,289	47,603	34,790	35,574	37,571	65,750	33,007	175,103	171,902	94,951
Parent Company
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Interest income									3,282	2,819	1,603
Interest expense									(23,037)	(27,252)	(22,816)
Gains on derivative instruments, net									17,289	34,654	6,570
Gains on investment securities, net									15,329	16,432	6,923
General and administrative expenses									(66,812)	(71,355)	(66,489)
Income tax benefit									12,200	7,468	24,918
Loss before net income of subsidiaries									(41,749)	(37,234)	(49,291)
Net income attributable to SVBFG									175,103	171,902	94,951
Net income available to common stockholders									175,103	171,902	94,951
Parent Company | Nonbank Subsidiaries
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Equity in undistributed net income of subsidiary									21,457	20,013	13,987
Parent Company | Bank Subsidiaries
Schedule of Condensed Consolidating Statement of Operations [Line Items]
Equity in undistributed net income of subsidiary									$ 195,395	$ 189,123	$ 130,255