XML 67 R36.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Derivative Financial Instruments (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2012
General Discussion of Derivative Instruments and Hedging Activities [Abstract] |
Summary Of Location And Amounts Of Derivative Fair Values In The Consolidated Balance Sheets | The following tables present the location and amounts of derivative fair values in the consolidated balance sheets and derivative gains and losses in the consolidated statements of operations:
| Asset Derivatives |  | Liability Derivatives
| December 31, 2012 |  | December 31, 2011 |  | December 31, 2012 |  | December 31, 2011
| (Amounts in thousands)
Non-hedging derivatives |  |  |  |  |  |  |
Interest rate contracts—Other liabilities | $ | 0 |  |  | $ | 0 |  |  | $ | (103 | ) |  | $ | (670 | )
Equity contracts—Short-term investments (Other liabilities) | 0 |  |  | 0 |  |  | (175 | ) |  | (655 | )
Total derivatives | $ | 0 |  |  | $ | 0 |  |  | $ | (278 | ) |  | $ | (1,325 | )
Schedule Of Derivative Gains And Losses In The Consolidated Statements Of Operations |
| Gain (Loss) Recognized in Comprehensive Income
| Year Ended December 31,
Derivatives Contracts for Cash Flow Hedges | 2012 |  | 2011 |  | 2010
| (Amounts in thousands)
Interest rate contracts—Other comprehensive income (loss) | $ | 0 |  |  | $ | 1,139 |  |  | $ | (220 | )
| Gain (Loss) Recognized in Income
| Year Ended December 31,
Derivatives Not Designated as Hedging Instruments | 2012 |  | 2011 |  | 2010
| (Amounts in thousands)
Interest rate contract—Other revenue (expense) | $ | 567 |  |  | $ | 1,232 |  |  | $ | (457 | )
Equity contracts—Net realized investment gains | 2,680 |  |  | 9,000 |  |  | 4,615 |
Total | $ | 3,247 |  |  | $ | 10,232 |  |  | $ | 4,158 |

X
- Definition Schedule of Derivative Gains and Losses in the Consolidated Statements of Operations [Table Text Block] + References No definition available. + Details
Name: | mcy_ScheduleOfDerivativeGainsAndLossesInConsolidatedStatementsOfOperationsTableTextBlock
Namespace Prefix: | mcy_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_GeneralDiscussionOfDerivativeInstrumentsAndHedgingActivitiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the location and fair value amounts of derivative instruments (and nonderivative instruments that are designated and qualify as hedging instruments) reported in the statement of financial position. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 205G -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 815 -SubTopic 10 -Section 50 -Paragraph 4B -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44C -Subparagraph a -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. + Details
Name: | us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration