Fair Values Valuation of Financial Instruments not reported at fair value (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financial Instruments Not Reported at Fair Value [Line Items]
Mortgage loans	$ 541,975	$ 552,359
Policy loans	172,786	172,368
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial Instruments Not Reported at Fair Value [Line Items]
Other liabilities	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Financial Instruments Not Reported at Fair Value [Line Items]
Other liabilities	94	64
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial Instruments Not Reported at Fair Value [Line Items]
Other liabilities	0	33,144
Portion at Other than Fair Value, Fair Value Disclosure [Member] \| Fair Value, Measurements, Recurring [Member]
Financial Instruments Not Reported at Fair Value [Line Items]
Mortgage loans	589,634
Policy loans	226,702
Total assets	816,336
Supplemental contracts without life contingencies	343,474
Future policy benefits	3,450,917
Long-term debt	113,774
Advance premiums and other deposits	212,654
Liabilities related to separate accounts	624,643
Total liabilities	4,745,462
Portion at Other than Fair Value, Fair Value Disclosure [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial Instruments Not Reported at Fair Value [Line Items]
Mortgage loans	0
Policy loans	0
Total assets	0
Supplemental contracts without life contingencies	0
Future policy benefits	0
Long-term debt	0
Advance premiums and other deposits	0
Liabilities related to separate accounts	0
Total liabilities	0
Portion at Other than Fair Value, Fair Value Disclosure [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Financial Instruments Not Reported at Fair Value [Line Items]
Mortgage loans	0
Policy loans	0
Total assets	0
Supplemental contracts without life contingencies	0
Future policy benefits	0
Long-term debt	0
Advance premiums and other deposits	0
Liabilities related to separate accounts	0
Total liabilities	0
Portion at Other than Fair Value, Fair Value Disclosure [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial Instruments Not Reported at Fair Value [Line Items]
Mortgage loans	589,634
Policy loans	226,702
Total assets	816,336
Supplemental contracts without life contingencies	343,474
Future policy benefits	3,450,917
Long-term debt	113,774
Advance premiums and other deposits	212,654
Liabilities related to separate accounts	624,643
Total liabilities	$ 4,745,462

Advance premiums and other deposits, fair value disclosure

No definition available.

Name:	fbl_AdvancePremiumsAndOtherDepositsFairValueDisclosure
Namespace Prefix:	fbl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Assets not measured at fair value

+ References

No definition available.

+ Details

Name:	fbl_AssetsNotMeasuredAtFairValue
Namespace Prefix:	fbl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	fbl_FinancialInstrumentsNotReportedAtFairValueLineItems
Namespace Prefix:	fbl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Future policy benefits not reported at fair value

+ References

No definition available.

+ Details

Name:	fbl_FuturePolicyBenefitsNotReportedAtFairValue
Namespace Prefix:	fbl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Liabilities not measured at fair value

+ References

No definition available.

+ Details

Name:	fbl_LiabilitiesNotMeasuredAtFairValue
Namespace Prefix:	fbl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Liabilities related to separate accounts, fair value disclosure

+ References

No definition available.

+ Details

Name:	fbl_LiabilitiesRelatedToSeparateAccountsFairValueDisclosure
Namespace Prefix:	fbl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Supplemental contracts without life contingencies, fair value disclosure

+ References

No definition available.

+ Details

Name:	fbl_SupplementalContractsWithoutLifeContingenciesFairValueDisclosure
Namespace Prefix:	fbl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Gross amount of loans made to policy and contract holders using their life insurance contracts' cash value or separate accounts as collateral.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-LHI

-Paragraph 104, 105, 106

-IssueDate 2006-05-01

-Chapter 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(a)(7))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(e))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph e

-Article 7

+ Details

Name:	us-gaap_LoansInsurancePolicy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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

- Definition

The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 60

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(c))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph c

-Article 7

+ Details

Name:	us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This element represents the fair value of liabilities categorized as other which are not in and of themselves material enough to require separate disclosure.

+ References

No definition available.

+ Details

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