v2.4.0.8
Segments - Net Income (Loss) and Total Assets (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Jun. 30, 2013
Segment
Jun. 30, 2012
Dec. 31, 2011
Dec. 31, 2012
Segment Reporting Information [Line Items]            
Number of operating segments     3      
Net Income (Loss) [Abstract]            
Net premiums written $ 497,949 $ 411,960 $ 1,187,008 $ 1,002,793    
Net premiums earned 513,273 437,116 1,001,715 875,612    
Other insurance revenue 2,780 2,274 7,995 7,028    
Net loss and loss adjustment expenses (343,347) (300,435) (678,242) (588,352)    
Commission and other acquisition expenses (143,572) (114,663) (275,902) (246,921)    
General and administrative expenses (11,837) (12,869) (23,298) (23,869)    
Underwriting income 17,297 11,423 32,268 23,498    
Reconciliation to net loss attributable to Maiden shareholders [Abstract]            
Net investment income and realized and unrealized gains (losses) on investment 20,692 17,146 45,954 36,948    
Amortization of intangible assets (945) (1,091) (1,890) (2,181)    
Foreign exchange and other (gains) losses 1,049 (874) 2,596 105 105  
Interest and amortization expenses (9,570) (9,568) (19,140) (17,246)    
Other general and administrative expenses (4,980) (2,339) (7,614) (5,170)    
Income tax expense (212) (91) (736) (970)    
Net income attributable to noncontrolling interest (32) (65) (59) (66)    
Dividends on preference shares (3,094) 0 (6,188) 0    
Net income attributable to Maiden common shareholders 20,205 14,541 45,191 34,918    
Net loss and loss expense ratio 66.50% [1] 68.40% [1] 67.20% [1] 66.70% [1]    
Acquisition cost ratio 27.80% [2] 26.10% [2] 27.30% [2] 28.00% [2]    
General and administrative expense ratio 3.30% [3] 3.40% [3] 3.10% [3] 3.20% [3]    
Combined ratio 97.60% [4] 97.90% [4] 97.60% [4] 97.90% [4]    
Assets [Abstract]            
Reinsurance balance receivable, net 685,095   685,095     522,614
Funds withheld 43,706   43,706     42,712
Prepaid reinsurance premiums 48,944   48,944     38,725
Reinsurance recoverable on unpaid losses 101,143   101,143     110,858
Deferred commissions and other acquisition expenses 314,839   314,839     270,669
Loan to related party 167,975   167,975     167,975
Goodwill and intangible assets, net 92,503   92,503     94,393
Restricted cash and cash equivalents and investments 2,156,970   2,156,970     2,167,318
Other assets 6,485   6,485     5,864
Total Assets - Operating Segments 3,617,660   3,617,660     3,421,128
Corporate assets 788,190 717,035 788,190 717,035    
Total assets 4,405,850   4,405,850     4,138,163
Diversified Reinsurance Segment [Member]
            
Net Income (Loss) [Abstract]            
Net premiums written 134,934 143,981 402,544 432,277    
Net premiums earned 178,336 199,130 374,585 403,593    
Other insurance revenue 2,780 2,274 7,995 7,028    
Net loss and loss adjustment expenses (120,837) (138,420) (261,600) (270,812)    
Commission and other acquisition expenses (44,438) (47,945) (89,220) (112,094)    
General and administrative expenses (11,153) (12,145) (21,951) (22,593)    
Underwriting income 4,688 2,894 9,809 5,122    
Reconciliation to net loss attributable to Maiden shareholders [Abstract]            
Net loss and loss expense ratio 66.70% [1] 68.70% [1] 68.40% [1] 66.00% [1]    
Acquisition cost ratio 24.50% [2] 23.80% [2] 23.30% [2] 27.30% [2]    
General and administrative expense ratio 6.20% [3] 6.10% [3] 5.70% [3] 5.50% [3]    
Combined ratio 97.40% [4] 98.60% [4] 97.40% [4] 98.80% [4]    
Assets [Abstract]            
Reinsurance balance receivable, net 304,635   304,635     260,161
Funds withheld 43,706   43,706     42,712
Prepaid reinsurance premiums 48,944   48,944     38,725
Reinsurance recoverable on unpaid losses 101,143   101,143     110,858
Deferred commissions and other acquisition expenses 84,080   84,080     83,287
Loan to related party 0   0     0
Goodwill and intangible assets, net 92,503   92,503     94,393
Restricted cash and cash equivalents and investments 1,096,736   1,096,736     1,219,454
Other assets 6,485   6,485     5,864
Total Assets - Operating Segments 1,778,232   1,778,232     1,855,454
Corporate assets 0   0     0
Total assets 1,778,232   1,778,232     1,855,454
AmTrust Quota Share Reinsurance Segment [Member]
            
Net Income (Loss) [Abstract]            
Net premiums written 290,578 195,629 635,396 421,644    
Net premiums earned 261,404 167,816 481,692 335,695    
Other insurance revenue 0 0 0 0    
Net loss and loss adjustment expenses (172,925) (116,755) (318,570) (229,611)    
Commission and other acquisition expenses (76,198) (44,590) (141,330) (91,759)    
General and administrative expenses (505) (530) (994) (909)    
Underwriting income 11,776 5,941 20,798 13,416    
Reconciliation to net loss attributable to Maiden shareholders [Abstract]            
Net loss and loss expense ratio 66.20% [1] 69.60% [1] 66.10% [1] 68.40% [1]    
Acquisition cost ratio 29.10% [2] 26.60% [2] 29.30% [2] 27.30% [2]    
General and administrative expense ratio 0.20% [3] 0.30% [3] 0.30% [3] 0.30% [3]    
Combined ratio 95.50% [4] 96.50% [4] 95.70% [4] 96.00% [4]    
Assets [Abstract]            
Reinsurance balance receivable, net 284,286   284,286     170,983
Funds withheld 0   0     0
Prepaid reinsurance premiums 0   0     0
Reinsurance recoverable on unpaid losses 0   0     0
Deferred commissions and other acquisition expenses 195,848   195,848     153,530
Loan to related party 167,975   167,975     167,975
Goodwill and intangible assets, net 0   0     0
Restricted cash and cash equivalents and investments 964,770   964,770     857,013
Other assets 0   0     0
Total Assets - Operating Segments 1,612,879   1,612,879     1,349,501
Corporate assets 0   0     0
Total assets 1,612,879   1,612,879     1,349,501
NGHC Quota Share Segment [Member]
            
Net Income (Loss) [Abstract]            
Net premiums written 72,437 72,350 149,068 148,872    
Net premiums earned 73,533 70,170 145,438 136,324    
Other insurance revenue 0 0 0 0    
Net loss and loss adjustment expenses (49,585) (45,260) (98,072) (87,929)    
Commission and other acquisition expenses (22,936) (22,128) (45,352) (43,068)    
General and administrative expenses (179) (194) (353) (367)    
Underwriting income 833 2,588 1,661 4,960    
Reconciliation to net loss attributable to Maiden shareholders [Abstract]            
Net loss and loss expense ratio 67.40% [1] 64.50% [1] 67.40% [1] 64.50% [1]    
Acquisition cost ratio 31.20% [2] 31.50% [2] 31.20% [2] 31.60% [2]    
General and administrative expense ratio 0.30% [3] 0.30% [3] 0.30% [3] 0.30% [3]    
Combined ratio 98.90% [4] 96.30% [4] 98.90% [4] 96.40% [4]    
Assets [Abstract]            
Reinsurance balance receivable, net 96,174   96,174     91,470
Funds withheld 0   0     0
Prepaid reinsurance premiums 0   0     0
Reinsurance recoverable on unpaid losses 0   0     0
Deferred commissions and other acquisition expenses 34,911   34,911     33,852
Loan to related party 0   0     0
Goodwill and intangible assets, net 0   0     0
Restricted cash and cash equivalents and investments 95,464   95,464     90,851
Other assets 0   0     0
Total Assets - Operating Segments 226,549   226,549     216,173
Corporate assets 0   0     0
Total assets $ 226,549   $ 226,549     $ 216,173
[1] Calculated by dividing net loss and loss adjustment expenses by the sum of net premiums earned and other insurance revenue.
[2] Calculated by dividing commission and other acquisition expenses by the sum of net premiums earned and other insurance revenue.
[3] Calculated by dividing general and administrative expenses by the sum of net premiums earned and other insurance revenue.
[4] Calculated by adding together net loss and loss adjustment expense ratio, commission and other acquisition expense ratio and general and administrative expense ratio.