XML 69 R54.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Investments (Estimated Fair Value Of Investments) (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2015 USD ($)
Fixed maturity securities: |
Due in one year or less | $ 108,775
Due after one year through five years | 394,240
Due after five years through ten years | 609,243
Due after ten years | 1,767,745
Total | $ 2,880,003
Percentage of fixed maturities | 1.30%

X
- Definition Percentage of fixed maturities rated below investment grade and non-rated. + References No definition available. + Details
Name: | mcy_PercentageOfFixedMaturitySecurities
Namespace Prefix: | mcy_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Trading securities debt maturities after five through ten years fair value. + References No definition available. + Details
Name: | mcy_TradingSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
Namespace Prefix: | mcy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Trading securities debt maturities after one through five years fair value. + References No definition available. + Details
Name: | mcy_TradingSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
Namespace Prefix: | mcy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Trading securities debt maturities after ten years fair value. + References No definition available. + Details
Name: | mcy_TradingSecuritiesDebtMaturitiesAfterTenYearsFairValue
Namespace Prefix: | mcy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Trading securities debt maturities within one year fair value. + References No definition available. + Details
Name: | mcy_TradingSecuritiesDebtMaturitiesWithinOneYearFairValue
Namespace Prefix: | mcy_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24584-111560 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Available-for-Sale Securities -URI http://asc.fasb.org/extlink&oid=6505594 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph a, f, g -Article 7 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_MarketableSecuritiesFixedMaturitiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration