Fair Value Measurement [Abstract]

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- Definition

Fair Value Measurement Inputs [Abstract]

+ References

No definition available.

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- Definition

Impaired Financing Receivable, Measurement Input

+ References

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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- Definition

Value of input used to measure real estate owned by financial institution by financial institution which is not directly related to its business.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

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- Definition

Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5162-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4437-111522

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- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746

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- Definition

Value of input used to measure servicing asset.

+ References

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Fair Value Measurements - Qualitative Valuation (Details)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Fair Value
Real estate owned	$ 0	$ 92,000
Measured on non-recurring basis
Fair Value
Impaired loans	3,546,000	1,525,000
Real estate owned		92,000
Mortgage servicing rights	527,000	442,000
Significant Unobservable Inputs (Level 3)
Fair Value
Impaired loans	4,917,066,000	4,841,830,000
Significant Unobservable Inputs (Level 3) \| Measured on non-recurring basis
Fair Value
Impaired loans	3,546,000	1,525,000	$ 1,525,000
Real estate owned		92,000	92,000
Mortgage servicing rights	$ 527,000	$ 442,000	$ 442,000
Significant Unobservable Inputs (Level 3) \| Discount Rate \| Measured on non-recurring basis \| Contract Sales Price
Unobservable Inputs
Real estate owned		0.060
Significant Unobservable Inputs (Level 3) \| Discount Rate \| Measured on non-recurring basis \| Minimum \| Appraisal
Unobservable Inputs
Impaired loans	0.060	0.060
Significant Unobservable Inputs (Level 3) \| Discount Rate \| Measured on non-recurring basis \| Maximum \| Appraisal
Unobservable Inputs
Impaired loans	0.080	0.080
Significant Unobservable Inputs (Level 3) \| Discount Rate \| Measured on non-recurring basis \| Weighted Average \| Appraisal
Unobservable Inputs
Impaired loans	0.063	0.075
Significant Unobservable Inputs (Level 3) \| Discount Rate \| Measured on non-recurring basis \| Weighted Average \| Contract Sales Price
Unobservable Inputs
Real estate owned		0.060
Significant Unobservable Inputs (Level 3) \| Prepayment Rate \| Measured on non-recurring basis \| Minimum \| Estimated Cash Flow
Unobservable Inputs
Mortgage servicing rights	0.037	0.033
Significant Unobservable Inputs (Level 3) \| Prepayment Rate \| Measured on non-recurring basis \| Maximum \| Estimated Cash Flow
Unobservable Inputs
Mortgage servicing rights	0.272	0.268
Significant Unobservable Inputs (Level 3) \| Prepayment Rate \| Measured on non-recurring basis \| Weighted Average \| Estimated Cash Flow
Unobservable Inputs
Mortgage servicing rights	0.134	0.120