Derivatives and Hedging - Credit and Market Risks (Details) - USD ($)		3 Months Ended
		Mar. 31, 2017		Mar. 31, 2016	Dec. 31, 2016
Derivatives [Line Items]
Gain (loss) related to hedge, firm commitments no longer qualifying as a fair value hedge		$ 0		$ 0
Derivative assets		203,289,000			$ 234,002,000
Derivative, collateral, right to reclaim cash	[1]	86,569,000			102,603,000
Derivative, collateral, obligation to return	[1]	41,212,000			33,212,000
Other Assets
Derivatives [Line Items]
Derivative, collateral, right to reclaim cash		87,000,000			103,000,000
Deposits
Derivatives [Line Items]
Derivative, collateral, obligation to return		44,000,000			37,000,000
Free-standing derivatives not designated as hedging instrument
Derivatives [Line Items]
Derivative assets	[2]	333,442,000	[3]		384,581,000
Free-standing derivatives not designated as hedging instrument | Interest Rate Swap
Derivatives [Line Items]
Gain (loss) on derivative instruments held for trading purposes, net		0
Gain (loss) on derivative instruments held for non-trading purposes, net		0		$ 0
Free-standing derivatives not designated as hedging instrument | Total trading account assets and liabilities
Derivatives [Line Items]
Derivative assets	[2]	268,158,000	[3]		318,605,000
Derivatives designated as hedging instrument
Derivatives [Line Items]
Derivative assets	[2]	32,440,000	[3]		41,230,000
Derivatives designated as hedging instrument | Interest Rate Swap | Over the Counter
Derivatives [Line Items]
Credit risk derivatives, at fair value, net		32,000,000
Cash flow hedges | Derivatives designated as hedging instrument
Derivatives [Line Items]
Derivative assets	[2]	$ 437,000	[3]		$ 2,340,000

[1] The actual amount of collateral received/pledged is limited to the asset/liability balance and does not include excess collateral received/pledged. When excess collateral exists, the collateral shown in the table above has been allocated based on the percentage of the actual amount of collateral posted.

[2] Derivative assets, except for trading account assets that are recorded as a component of trading account assets on the Company's Unaudited Condensed Consolidated Balance Sheets, are recorded in other assets on the Company’s Unaudited Condensed Consolidated Balance Sheets.

[3] In January 2017, a clearing organization adopted a rule change that requires transactions to be considered settled-to-market each day. Beginning in the first quarter of 2017, to the extent the Company determined transactions with this clearing organization to be settled-to-market, the impact was a reduction to the derivative assets and liabilities as well as a corresponding decrease in cash collateral.