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Shareholders' Equity (Details) (USD $)
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3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 0 Months Ended | 0 Months Ended | 3 Months Ended | 9 Months Ended | 0 Months Ended | ||||||||||||
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Sep. 30, 2013
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Sep. 30, 2012
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Sep. 30, 2013
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Sep. 30, 2012
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Dec. 31, 2012
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Sep. 30, 2013
Change in net unrealized gains on investments [Member]
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Sep. 30, 2012
Change in net unrealized gains on investments [Member]
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Sep. 30, 2013
Change in net unrealized gains on investments [Member]
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Sep. 30, 2012
Change in net unrealized gains on investments [Member]
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Sep. 30, 2013
Foreign currency translation adjustments [Member]
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Sep. 30, 2012
Foreign currency translation adjustments [Member]
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Sep. 30, 2013
Foreign currency translation adjustments [Member]
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Sep. 30, 2012
Foreign currency translation adjustments [Member]
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Sep. 30, 2013
Preference Shares - Series B [Member]
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Sep. 25, 2013
Preference Shares - Series B [Member]
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Sep. 30, 2013
Preference Shares - Series B [Member]
Maximum [Member]
director
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Sep. 30, 2013
Preference Shares - Series B [Member]
Minimum [Member]
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Aug. 22, 2012
Preference Shares - Series A [Member]
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Sep. 30, 2013
Preference Shares - Series A [Member]
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Sep. 30, 2012
Preference Shares - Series A [Member]
|
Sep. 30, 2013
Preference Shares - Series A [Member]
|
Sep. 30, 2012
Preference Shares - Series A [Member]
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Sep. 30, 2013
Preference Shares - Series A [Member]
Maximum [Member]
director
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| Class of Stock [Line Items] | |||||||||||||||||||||||
| Common stock, shares authorized (in shares) | 150,000,000 | 150,000,000 | |||||||||||||||||||||
| Common stock, shares issued (in shares) | 73,575,384 | 73,575,384 | 73,306,283 | ||||||||||||||||||||
| Common stock, shares outstanding (in shares) | 72,613,048 | 72,613,048 | 72,343,947 | ||||||||||||||||||||
| Preference shares issued (in shares) | 6,000,000 | 6,000,000 | 6,000,000 | 6,000,000 | |||||||||||||||||||
| Preference shares, subscribed but unissued (in shares) | 3,000,000 | 3,000,000 | 3,000,000 | ||||||||||||||||||||
| Preference shares authorized (in shares) | 300,000 | 300,000 | 3,300,000 | 6,000,000 | 6,000,000 | ||||||||||||||||||
| Preference shares offered (in shares) | 3,000,000 | ||||||||||||||||||||||
| Dividend rate of Preference Shares | 7.25% | 8.25% | |||||||||||||||||||||
| Number of Preference Shares issued (in shares) | 6,000,000 | ||||||||||||||||||||||
| Share price (in dollars per share) | $ 50 | $ 25.000 | |||||||||||||||||||||
| Preference shares, issuance costs (in dollars per share) | $ 1.50 | ||||||||||||||||||||||
| Sale price of Preference Shares (in dollars per share) | $ 50 | $ 25.00 | |||||||||||||||||||||
| Preference shares, liquidation preference per share per annum (in dollars per share) | $ 3.625 | ||||||||||||||||||||||
| Preference shares, liquidation preference per share per quarter (in dollars per share) | $ 0.90625 | ||||||||||||||||||||||
| Preference shares, liquidation preference per share in initial quarter (in dollars per share) | $ 0.745139 | ||||||||||||||||||||||
| Convertible Preference shares, Number of common shares issued upon conversion (in shares) | 4.0322 | 3.2258 | |||||||||||||||||||||
| Par value of Preference Shares (in dollars per share) | $ 0.01 | ||||||||||||||||||||||
| Preference shares, number of electable board members (in directors) | 2 | 2 | |||||||||||||||||||||
| Convertible Preference shares, conversion rate measurement period | 40 days | ||||||||||||||||||||||
| Preference shares, dividend rate (in dollars per share) | $ 0.09 | ||||||||||||||||||||||
| Proceeds from issuance of Preference Shares | $ 0 | $ 145,041,000 | $ 145,041,000 | ||||||||||||||||||||
| Expenses and underwriting discounts | 4,959,000 | ||||||||||||||||||||||
| Preference shares, outstanding (in shares) | 6,000,000 | 6,000,000 | |||||||||||||||||||||
| Redemption price for Preference Shares (in dollars per share) | $ 25.000 | ||||||||||||||||||||||
| Dividends on Preference shares | 3,093,000 | 0 | 9,281,000 | 0 | 3,093,000 | 0 | 9,281,000 | 0 | |||||||||||||||
| Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward] | |||||||||||||||||||||||
| Beginning balance | 48,025,000 | 95,552,000 | 141,126,000 | 64,051,000 | 49,247,000 | 93,830,000 | 143,665,000 | 63,737,000 | (1,222,000) | 1,722,000 | (2,539,000) | 314,000 | |||||||||||
| Other comprehensive income (loss) before reclassifications | 1,178,000 | 44,286,000 | (88,842,000) | 75,806,000 | 5,922,000 | 45,986,000 | (85,415,000) | 76,098,000 | (4,744,000) | (1,700,000) | (3,427,000) | (292,000) | |||||||||||
| Amounts reclassified from accumulated other comprehensive income | (576,000) | (2,410,000) | (3,657,000) | (2,429,000) | (576,000) | (2,410,000) | (3,657,000) | (2,429,000) | 0 | 0 | 0 | 0 | |||||||||||
| Other comprehensive income (loss) | 602,000 | 41,876,000 | (92,499,000) | 73,377,000 | 5,346,000 | 43,576,000 | (89,072,000) | 73,669,000 | (4,744,000) | (1,700,000) | (3,427,000) | (292,000) | |||||||||||
| Ending balance | 48,627,000 | 137,428,000 | 48,627,000 | 137,428,000 | 54,593,000 | 137,406,000 | 54,593,000 | 137,406,000 | (5,966,000) | 22,000 | (5,966,000) | 22,000 | |||||||||||
| Less: Accumulated other comprehensive income attributable to non controlling interest | 8,000 | (13,000) | 8,000 | (13,000) | 0 | 0 | 0 | 0 | 8,000 | (13,000) | 8,000 | (13,000) | |||||||||||
| Ending balance, Maiden shareholders | $ 48,619,000 | $ 137,441,000 | $ 48,619,000 | $ 137,441,000 | $ 141,130,000 | $ 54,593,000 | $ 137,406,000 | $ 54,593,000 | $ 137,406,000 | $ (5,974,000) | $ 35,000 | $ (5,974,000) | $ 35,000 | ||||||||||