Derivatives and Hedging Activities - Derivatives not designated as hedging instruments under ASC 815 (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, assets at fair value	$ 24,705	$ 22,385
Interest rate derivative instruments not designated as hedging instruments, liabilities at fair value	24,751	23,323
Derivative assets \| Customer derivative positions
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, assets at fair value	5,216	2,659
Derivative assets \| Dealer offsets to customer derivative positions
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, assets at fair value	7,620	6,867
Derivative assets \| Mortgage banking - loan commitment
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, assets at fair value	1,190	1,150
Derivative assets \| Mortgage banking - forward sales commitment
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, assets at fair value	28	13
Derivative assets \| Bifurcated embedded derivatives
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, assets at fair value	10,651	11,057
Derivative assets \| Interest rate caps
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, assets at fair value	0	639
Derivative liabilities \| Customer derivative positions
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, liabilities at fair value	9,661	7,032
Derivative liabilities \| Dealer offsets to customer derivative positions
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, liabilities at fair value	781	1,551
Derivative liabilities \| Risk participations
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, liabilities at fair value	8	20
Derivative liabilities \| Mortgage banking - forward sales commitment
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, liabilities at fair value	259	49
Derivative liabilities \| Dealer offsets to bifurcated embedded derivatives
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, liabilities at fair value	13,339	14,279
Derivative liabilities \| De-designated hedges
Derivatives, Fair Value [Line Items]
Interest rate derivative instruments not designated as hedging instruments, liabilities at fair value	$ 703	$ 392

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- Definition

Fair value as of the balance sheet date of all derivative assets not designated as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959

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- Definition

Fair value as of the balance sheet date of all derivative liabilities not designated as hedging instruments.

+ References

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