Derivative Instruments and Hedging Activities (Details) - Offsetting Derivatives (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 9,018		$ 2,235
Less: amounts offset in the Consolidated Statements of Financial Condition	0		0
Net amount presented in the Consolidated Statements of Financial Condition	9,018	[1]	2,235	[1]
Offsetting derivative positions	(1,195)		(704)
Cash collateral pledged	0		0
Derivative Asset, Net credit exposure	7,823		1,531
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	11,980		3,707
Less: amounts offset in the Consolidated Statements of Financial Condition	0		0
Net amount presented in the Consolidated Statements of Financial Condition	11,980	[1]	3,707	[1]
Offsetting derivative positions	(1,195)		(704)
Cash collateral pledged	(10,785)		(3,003)
Net credit exposure	$ 0		$ 0

[1] Included in other assets or other liabilities in the Consolidated Statements of Financial Condition.