Derivative Liabilities and Collateral Pledged (Details) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Derivative [Line Items]
Gross amounts of recognized liabilities		$ 170,619	$ 108,339	$ 109,815
Derivative Liabilities not subject to master netting agreements		26,500		9,600
Derivatives, Interest Rate Contracts | Subject to Master Netting Agreements
Derivative [Line Items]
Gross amounts of recognized liabilities	[1]	144,165		100,191
Gross amounts offset in the Statement of Condition	[1]	0		0
Net amounts of liabilities presented in the Statement of Condition	[1],[2]	144,165		100,191
Derivative assets available for offset	[1]	(13,963)		(15,750)
Collateral pledged	[1]	(67,682)		(68,775)
Net amount	[1]	$ 62,520		$ 15,666

[1] 2016 and 2015 are comprised entirely of interest rate derivative contracts.

[2] In cluded in Derivative l iabilities on the Consolidated Condensed Statements of Condition. As of June 30 , 2016 and 2015 , $ 26 . 5 million and $ 9.6 million, respectively, of derivative liabilities (primarily fixed income forward contracts) have been excluded from these tables because they are generally not subject to master netting or similar agreements.