Derivatives and Hedging Activities Cash Flow Hedges Text Description (Details) $ in Millions	6 Months Ended
Jun. 30, 2018 USD ($) contracts
Derivative [Line Items]
Objectives for Using Derivative Instruments	The Company’s objectives in using interest rate derivatives are to add stability to interest income and expense and to manage its exposure to interest rate movements.
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	$ 1.2
Private Banking Segment [Member]
Derivative [Line Items]
Number of Interest Rate Derivatives Held \| contracts	6
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 8/1/13 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Objectives for Using Derivative Instruments	The interest rate swaps will effectively fix the Bank’s interest payments on $100 million of its LIBOR-indexed deposit liabilities
Derivative, Inception Date	Aug. 01, 2013
Derivative Asset, Notional Amount	$ 25.0
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 8/1/13 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Minimum [Member]
Derivative [Line Items]
Derivative, Term of Contract	4 years
Derivative, Fixed Interest Rate	1.68%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 8/1/13 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Maximum [Member]
Derivative [Line Items]
Derivative, Term of Contract	6 years
Derivative, Fixed Interest Rate	2.32%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 8/1/13 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Weighted Average [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	1.95%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 3/1/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Objectives for Using Derivative Instruments	The interest rate swaps will effectively fix the Bank’s interest payments on $100 million of its LIBOR-indexed deposit liabilities
Derivative, Inception Date	Mar. 01, 2014
Derivative Asset, Notional Amount	$ 25.0
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 3/1/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Minimum [Member]
Derivative [Line Items]
Derivative, Term of Contract	4 years
Derivative, Fixed Interest Rate	1.68%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 3/1/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Maximum [Member]
Derivative [Line Items]
Derivative, Term of Contract	6 years
Derivative, Fixed Interest Rate	2.32%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 3/1/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Weighted Average [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	1.95%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap 2013 effective 6/1/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Objectives for Using Derivative Instruments	The interest rate swaps will effectively fix the Bank’s interest payments on $100 million of its LIBOR-indexed deposit liabilities
Derivative, Inception Date	Jun. 01, 2014
Derivative Asset, Notional Amount	$ 25.0
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap 2013 effective 6/1/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Minimum [Member]
Derivative [Line Items]
Derivative, Term of Contract	4 years
Derivative, Fixed Interest Rate	1.68%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap 2013 effective 6/1/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Maximum [Member]
Derivative [Line Items]
Derivative, Term of Contract	6 years
Derivative, Fixed Interest Rate	2.32%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap 2013 effective 6/1/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Weighted Average [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	1.95%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 9/2/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Objectives for Using Derivative Instruments	The interest rate swaps will effectively fix the Bank’s interest payments on $100 million of its LIBOR-indexed deposit liabilities
Derivative, Inception Date	Sep. 02, 2014
Derivative Asset, Notional Amount	$ 25.0
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 9/2/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Minimum [Member]
Derivative [Line Items]
Derivative, Term of Contract	4 years
Derivative, Fixed Interest Rate	1.68%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 9/2/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Maximum [Member]
Derivative [Line Items]
Derivative, Term of Contract	6 years
Derivative, Fixed Interest Rate	2.32%
Interest Rate Swap [Member] \| Bank $25m LIBOR Swap effective 9/2/14 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Weighted Average [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	1.95%
Interest Rate Swap [Member] \| Bank $40m LIBOR Swap 2017 effective 3/22/17 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Objectives for Using Derivative Instruments	These interest rate swaps will effectively fix the Bank’s interest payments on $100 million in interest-related cash outflows attributable to changes in the LIBOR component of FHLB borrowing liabilities
Derivative, Inception Date	Mar. 22, 2017
Derivative Asset, Notional Amount	$ 40.0
Derivative, Term of Contract	1 year 9 months
Derivative, Fixed Interest Rate	1.55%
Interest Rate Swap [Member] \| Bank $40m LIBOR Swap 2017 effective 3/22/17 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Weighted Average [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	1.61%
Interest Rate Swap [Member] \| Bank $60m LIBOR Swap 2017 effective 3/22/17 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Objectives for Using Derivative Instruments	These interest rate swaps will effectively fix the Bank’s interest payments on $100 million in interest-related cash outflows attributable to changes in the LIBOR component of FHLB borrowing liabilities
Derivative, Inception Date	Mar. 22, 2017
Derivative Asset, Notional Amount	$ 60.0
Derivative, Term of Contract	2 years 3 months
Derivative, Fixed Interest Rate	1.65%
Interest Rate Swap [Member] \| Bank $60m LIBOR Swap 2017 effective 3/22/17 [Member] \| Private Banking Segment [Member] \| Designated as Hedging Instrument [Member] \| Weighted Average [Member]
Derivative [Line Items]
Derivative, Fixed Interest Rate	1.61%

Nominal or face amount used to calculate payments on the derivative asset.

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-Name Accounting Standards Codification
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Fixed interest rate related to the interest rate derivative.

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Number of interest rate derivative instruments held by the entity at the reporting date.

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Description of the reasons for holding or issuing derivative instruments and nonderivative hedging instruments. Includes discussion of the objectives for holding or issuing derivative instruments, the context needed to understand those objectives, and the strategies for achieving those objectives. The description generally distinguishes between derivative and nonderivative instruments by the types of hedging relationships and between those instruments used for risk management purposes and those used for other purposes. Information about those instruments is disclosed in the context of each instrument's primary underlying risk exposure (for example, interest rate, credit, foreign exchange rate, interest rate and foreign exchange rate, or overall price).

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