Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments Recorded Investment in Loans Modified in TDRs within Previous 12 months Subsequently Defaulted (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Financing Receivable, Modifications [Line Items]
Financing receivable modifications recorded investment subsequently defaulted	$ 190	$ 1,980	$ 190	$ 1,980
Commercial Portfolio Segment | Software/internet
Financing Receivable, Modifications [Line Items]
Financing receivable modifications recorded investment subsequently defaulted	0	1,474	0	1,474
Commercial Portfolio Segment | Premium wine
Financing Receivable, Modifications [Line Items]
Financing receivable modifications recorded investment subsequently defaulted	$ 190	$ 506	$ 190	$ 506