Parent Company Only Condensed Financial Information Condensed Statement of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Net income available to common stockholders	$ 117,210	$ 148,620	$ 123,193	$ 101,483	$ 99,466	$ 111,081	$ 92,964	$ 79,174	$ 490,506	[1]	$ 382,685	$ 343,904
Other comprehensive income (loss), net of tax									(24,902)		8,026	(27,300)
Comprehensive income attributable to SVBFG									465,604		390,711	316,604
Parent Company
Net income available to common stockholders									490,506		382,685	343,904
Foreign currency translation gains (losses)									3,769		3,071	(1,492)
Unrealized holding gains (losses) on securities available for sale									22,285		654	(2,041)
Equity in other comprehensive income (losses) of subsidiaries									(50,956)		4,301	(23,767)
Other comprehensive income (loss), net of tax									(24,902)		8,026	(27,300)
Comprehensive income attributable to SVBFG									$ 465,604		$ 390,711	$ 316,604

[1] Included in income tax expense, net income available to common stockholders, earnings per common share-basic and earnings for common share-diluted, for the year ended December 31, 2017, are tax benefits recognized associated with the adoption of Accounting Standards Update ("ASU") 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts.