v2.4.0.6
Results of Operations of Business Segments (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Segment Reporting Information [Line Items]        
Gross written premium $ 736,556 $ 561,222 $ 1,975,681 $ 1,563,711
Net written premium 483,659 321,903 1,235,025 931,603
Change in unearned premium (96,212) (33,055) (199,560) (194,135)
Net earned premium 387,447 288,848 1,035,465 737,468
Ceding commission - primarily related party 49,860 40,732 140,684 111,830
Loss and loss adjustment expense (255,646) (185,352) (667,362) (484,056)
Acquisition costs and other underwriting expenses (143,736) (113,270) (397,474) (284,084)
Operating Expenses (399,382) (298,622) (1,064,836) (768,140)
Underwriting income 37,925 30,958 111,313 81,158
Service and fee income 44,561 28,815 118,110 78,546
Investment income and realized gain (loss) 20,642 15,006 53,059 43,396
Other expenses (42,337) (24,045) (110,296) (62,805)
Interest expense (7,218) (3,946) (21,303) (12,034)
Foreign currency gain (loss) (951) (4,063) (2,985) (1,827)
Life Settlement Contracts, Fair Value Method, Unrealized Gain (Loss)     5,302 48,346
Gain on Purchase of Business 0 5,850 0 5,850
Gain on life settlement contracts 3,251 6,822 5,302 48,346
Provision for income taxes (13,187) (14,297) (36,106) (30,623)
Equity in earnings (loss) of unconsolidated subsidiary - related party 3,207 (918) 8,659 3,415
Non-controlling interest (2,663) (3,016) (3,079) (20,911)
Net income attributable to Am Trust Financial Services, Inc. 43,230 37,166 122,674 132,511
Small Commercial Business
        
Segment Reporting Information [Line Items]        
Gross written premium 243,603 145,418 690,081 460,741
Net written premium 133,492 79,070 356,652 269,942
Change in unearned premium (9,686) 10,807 (46,950) (44,170)
Net earned premium 123,806 89,877 309,702 225,772
Ceding commission - primarily related party 17,845 16,312 50,435 48,207
Loss and loss adjustment expense (81,727) (55,721) (201,256) (142,411)
Acquisition costs and other underwriting expenses (48,317) (42,074) (133,412) (108,483)
Operating Expenses (130,044) (97,795) (334,668) (250,894)
Underwriting income 11,607 8,394 25,469 23,085
Service and fee income 12,403 6,347 38,383 16,765
Investment income and realized gain (loss) 6,803 6,590 19,055 19,399
Other expenses (13,660) (7,432) (38,525) (19,457)
Interest expense (2,288) (1,219) (7,441) (3,728)
Foreign currency gain (loss) 0 0 0 0
Life Settlement Contracts, Fair Value Method, Unrealized Gain (Loss)     1,851 14,978
Gain on Purchase of Business   5,850   5,850
Gain on life settlement contracts 1,100 2,096    
Provision for income taxes (3,563) (4,918) (8,653) (9,645)
Equity in earnings (loss) of unconsolidated subsidiary - related party 0 0 0 0
Non-controlling interest (922) (928) (1,075) (6,479)
Net income attributable to Am Trust Financial Services, Inc. 11,480 14,780 29,064 40,768
Specialty Risk and Extended Warranty
        
Segment Reporting Information [Line Items]        
Gross written premium 260,415 256,493 767,114 749,743
Net written premium 137,106 149,238 450,526 438,963
Change in unearned premium (21,371) (22,454) (57,611) (117,971)
Net earned premium 115,735 126,784 392,915 320,992
Ceding commission - primarily related party 13,226 14,928 46,594 41,614
Loss and loss adjustment expense (72,812) (83,102) (241,883) (216,579)
Acquisition costs and other underwriting expenses (36,126) (39,187) (123,249) (97,493)
Operating Expenses (108,938) (122,289) (365,132) (314,072)
Underwriting income 20,023 19,423 74,377 48,534
Service and fee income 23,605 18,413 57,252 49,823
Investment income and realized gain (loss) 7,519 4,956 20,683 14,962
Other expenses (14,713) (9,857) (42,826) (29,366)
Interest expense (2,444) (1,556) (8,271) (5,627)
Foreign currency gain (loss) (951) (4,063) (2,985) (1,827)
Life Settlement Contracts, Fair Value Method, Unrealized Gain (Loss)     2,059 22,605
Gain on Purchase of Business   0   0
Gain on life settlement contracts 1,211 1,705    
Provision for income taxes (7,646) (7,666) (22,372) (16,802)
Equity in earnings (loss) of unconsolidated subsidiary - related party 0 0 0 0
Non-controlling interest (1,024) (770) (1,196) (9,777)
Net income attributable to Am Trust Financial Services, Inc. 25,580 20,585 76,721 72,525
Specialty Program
        
Segment Reporting Information [Line Items]        
Gross written premium 202,280 132,621 428,796 275,951
Net written premium 182,803 66,905 338,157 145,422
Change in unearned premium (63,560) (19,958) (88,385) (27,567)
Net earned premium 119,243 46,947 249,772 117,855
Ceding commission - primarily related party 18,789 9,492 43,655 22,009
Loss and loss adjustment expense (82,619) (30,376) (170,639) (78,443)
Acquisition costs and other underwriting expenses (50,551) (23,806) (115,475) (54,432)
Operating Expenses (133,170) (54,182) (286,114) (132,875)
Underwriting income 4,862 2,257 7,313 6,989
Service and fee income 1,294 5 1,313 10
Investment income and realized gain (loss) 5,624 2,997 11,432 7,502
Other expenses (11,771) (6,386) (23,938) (11,549)
Interest expense (2,102) (1,136) (4,624) (2,213)
Foreign currency gain (loss) 0 0 0 0
Life Settlement Contracts, Fair Value Method, Unrealized Gain (Loss)     1,151 8,890
Gain on Purchase of Business   0   0
Gain on life settlement contracts 784 3,358    
Provision for income taxes 292 (519) 1,640 (1,632)
Equity in earnings (loss) of unconsolidated subsidiary - related party 0 0 0 0
Non-controlling interest (594) (1,461) (668) (3,845)
Net income attributable to Am Trust Financial Services, Inc. (1,611) (885) (6,381) 4,152
Personal Lines Reinsurance
        
Segment Reporting Information [Line Items]        
Gross written premium 30,258 26,690 89,690 77,276
Net written premium 30,258 26,690 89,690 77,276
Change in unearned premium (1,595) (1,450) (6,614) (4,427)
Net earned premium 28,663 25,240 83,076 72,849
Ceding commission - primarily related party 0 0 0 0
Loss and loss adjustment expense (18,488) (16,153) (53,584) (46,623)
Acquisition costs and other underwriting expenses (8,742) (8,203) (25,338) (23,676)
Operating Expenses (27,230) (24,356) (78,922) (70,299)
Underwriting income 1,433 884 4,154 2,550
Service and fee income 0 0 0 0
Investment income and realized gain (loss) 696 463 1,889 1,533
Other expenses (2,193) (370) (5,007) (2,433)
Interest expense (384) (35) (967) (466)
Foreign currency gain (loss) 0 0 0 0
Life Settlement Contracts, Fair Value Method, Unrealized Gain (Loss)     241 1,873
Gain on Purchase of Business   0   0
Gain on life settlement contracts 156 (337)    
Provision for income taxes 66 (198) (69) (518)
Equity in earnings (loss) of unconsolidated subsidiary - related party 0 0 0 0
Non-controlling interest (123) 143 (140) (810)
Net income attributable to Am Trust Financial Services, Inc. (349) 550 101 1,729
Corporate and Other
        
Segment Reporting Information [Line Items]        
Underwriting income 0 0 0 0
Service and fee income 7,259 4,050 21,162 11,948
Investment income and realized gain (loss) 0 0 0 0
Other expenses 0 0 0 0
Interest expense 0 0 0 0
Foreign currency gain (loss) 0 0 0 0
Life Settlement Contracts, Fair Value Method, Unrealized Gain (Loss)     0 0
Gain on Purchase of Business   0   0
Gain on life settlement contracts 0 0    
Provision for income taxes (2,336) (996) (6,652) (2,026)
Equity in earnings (loss) of unconsolidated subsidiary - related party 3,207 (918) 8,659 3,415
Non-controlling interest 0 0 0 0
Net income attributable to Am Trust Financial Services, Inc. $ 8,130 $ 2,136 $ 23,169 $ 13,337