A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

Name:	us-gaap_AOCIAttributableToParentNetOfTaxRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

+ References

No definition available.

+ Details

Name:	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 55
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=109228884&loc=d3e1436-108581

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669686-108580

+ Details

Name:	us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount after tax of other comprehensive income (loss) attributable to parent entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669625-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569643-111683

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669619-108580

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569616-111683

+ Details

Name:	us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669686-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 55
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=109228884&loc=d3e1436-108581

+ Details

Name:	us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(31))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockholdersEquity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201601Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201712Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedOtherThanTemporaryImpairmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedOtherComprehensiveIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Accumulated Other Comprehensive Loss - Components of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018
Accumulated Other Comprehensive Income (Loss)
Beginning balance			$ 2,533,165
Beginning balance after reclassifications	$ 3,302,936		2,533,165
Other comprehensive (loss) income before reclassifications	(8,462)		(33,493)
Amounts reclassified from other comprehensive (loss) income	642	$ 1,147	3,095	$ 3,970
Total other comprehensive (loss) income	(7,820)	2,579	(30,398)	7,993
Ending balance	3,302,936		3,302,936
Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			(480)
Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			(61)
Unrealized Gains and Losses on Available for Sale (AFS) Securities
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(39,296)		(12,004)
Beginning balance after reclassifications	(39,296)		(12,004)		$ (12,484)
Other comprehensive (loss) income before reclassifications	(8,675)		(36,065)
Amounts reclassified from other comprehensive (loss) income	52		630
Total other comprehensive (loss) income	(8,623)		(35,435)
Ending balance	(47,919)		(47,919)
Unrealized Gains and Losses on Available for Sale (AFS) Securities \| Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			(480)
Unrealized Gains and Losses on Available for Sale (AFS) Securities \| Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			0
Non-credit Impairment Losses on AFS Securities
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(440)		(380)
Beginning balance after reclassifications	(440)		(380)		(380)
Other comprehensive (loss) income before reclassifications	(8)		(64)
Amounts reclassified from other comprehensive (loss) income	5		1
Total other comprehensive (loss) income	(3)		(63)
Ending balance	(443)		(443)
Non-credit Impairment Losses on AFS Securities \| Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			0
Non-credit Impairment Losses on AFS Securities \| Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			0
Unrealized Gains and (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(4,329)		(8,338)
Beginning balance after reclassifications	(4,329)		(8,338)		(8,399)
Other comprehensive (loss) income before reclassifications	221		2,636
Amounts reclassified from other comprehensive (loss) income	472		2,127
Total other comprehensive (loss) income	693		4,763
Ending balance	(3,636)		(3,636)
Unrealized Gains and (Losses) on Derivatives \| Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			0
Unrealized Gains and (Losses) on Derivatives \| Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			(61)
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(25,059)		(25,283)
Beginning balance after reclassifications	(25,059)		(25,283)		(25,283)
Other comprehensive (loss) income before reclassifications	0		0
Amounts reclassified from other comprehensive (loss) income	113	$ 59	337	$ 177
Total other comprehensive (loss) income	113		337
Ending balance	(24,946)		(24,946)
Defined Benefit Pension Plan \| Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			0
Defined Benefit Pension Plan \| Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss)
Reclassification due to adoption of new accounting principle			0
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(69,124)		(46,005)
Beginning balance after reclassifications	(69,124)		(46,005)		$ (46,546)
Ending balance	$ (76,944)		$ (76,944)