Condensed Consolidated Financial Information for Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Condensed Consolidating Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 97,770	$ 191,603	$ 52,846	$ 54,974
Available-for-sale securities	4,895	5,066
Accounts receivable, net of allowance for doubtful accounts of $4,158	175,520	153,339
Prepaid expenses	25,387	21,905
Deferred income taxes, net	15,614	3,818
Federal and foreign income taxes receivable	8,538	25,242
State and local income taxes receivable		11,433
Other current assets	33,613	41,248
Total current assets	361,337	453,654
Noncurrent assets:
Fixed assets, net	144,799	119,411
Intangible assets, net	530,023	226,424
Goodwill	1,220,384	709,944
Deferred income taxes, net		10,480
Other assets	46,890	21,193
Total assets	2,303,433	1,541,106
Current liabilities:
Accounts payable and accrued liabilities	176,464	162,992
Acquisition related liabilities		250
Short-term debt and current portion of long-term debt	265,794	5,554
Pension and postretirement benefits, current	2,912	4,012
Fees received in advance	219,800	176,842
State and local income taxes payable	3,287
Total current liabilities	668,257	349,650
Noncurrent liabilities:
Long-term debt	1,301,683	1,100,332
Pension and postretirement benefits	27,891	127,748
Deferred income taxes, net	80,755
Other liabilities	82,799	61,866
Total liabilities	2,161,385	1,639,596
Total stockholders' (deficit) equity	142,048	(98,490)		(114,442)
Total liabilities and stockholders' (deficit) equity	2,303,433	1,541,106
Verisk Analytics, Inc. [Member]
Current assets:
Cash and cash equivalents	378	76,238	197	1
Federal and foreign income taxes receivable	10,349	7,905
State and local income taxes receivable	806	618
Intercompany receivables	375,417	250,177
Other current assets	12,005
Total current assets	398,955	334,938
Noncurrent assets:
Investment in subsidiaries	852,866	601,380
Other assets	14,171	6,218
Total assets	1,265,992	942,536
Current liabilities:
Accounts payable and accrued liabilities	15,434	6,328
Intercompany payables	64,282	338,041
Total current liabilities	79,716	344,369
Noncurrent liabilities:
Long-term debt	1,044,228	696,657
Total liabilities	1,123,944	1,041,026
Total stockholders' (deficit) equity	142,048	(98,490)
Total liabilities and stockholders' (deficit) equity	1,265,992	942,536
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	41,459	76,813	25,275	31,576
Available-for-sale securities	4,895	5,066
Accounts receivable, net of allowance for doubtful accounts of $4,158	125,456	128,214
Prepaid expenses	22,839	20,090
Deferred income taxes, net	2,558	2,557
Federal and foreign income taxes receivable	7,150	23,024
State and local income taxes receivable		10,392
Intercompany receivables	194,718	482,172
Other current assets	12,887	26,094
Total current assets	411,962	774,422
Noncurrent assets:
Fixed assets, net	117,436	102,202
Intangible assets, net	67,140	81,828
Goodwill	486,250	481,736
Deferred income taxes, net	49,557	50,267
Investment in subsidiaries	900,914	104,430
Other assets	30,661	13,059
Total assets	2,063,920	1,607,944
Current liabilities:
Accounts payable and accrued liabilities	103,094	117,759
Short-term debt and current portion of long-term debt	265,398	5,161
Pension and postretirement benefits, current	2,912	4,012
Fees received in advance	185,267	152,948
Intercompany payables	531,164	354,362
State and local income taxes payable	4,283
Total current liabilities	1,092,118	634,242
Noncurrent liabilities:
Long-term debt	257,388	403,586
Pension and postretirement benefits	27,891	127,748
Other liabilities	51,406	58,158
Total liabilities	1,428,803	1,223,734
Total stockholders' (deficit) equity	635,117	384,210
Total liabilities and stockholders' (deficit) equity	2,063,920	1,607,944
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	55,933	38,552	27,374	23,397
Accounts receivable, net of allowance for doubtful accounts of $4,158	50,064	25,125
Prepaid expenses	2,548	1,815
Deferred income taxes, net	13,056	1,261
State and local income taxes receivable	190	423
Intercompany receivables	216,560	147,996
Other current assets	8,721	15,154
Total current assets	347,072	230,326
Noncurrent assets:
Fixed assets, net	27,363	17,209
Intangible assets, net	462,883	144,596
Goodwill	734,134	228,208
Other assets	2,058	1,916
Total assets	1,573,510	622,255
Current liabilities:
Accounts payable and accrued liabilities	57,936	38,905
Acquisition related liabilities		250
Short-term debt and current portion of long-term debt	396	393
Fees received in advance	34,533	23,894
Intercompany payables	191,249	187,942
Federal and foreign income taxes payable	8,961	5,687
Total current liabilities	293,075	257,071
Noncurrent liabilities:
Long-term debt	67	89
Deferred income taxes, net	130,312	39,787
Other liabilities	31,393	3,708
Total liabilities	454,847	300,655
Total stockholders' (deficit) equity	1,118,663	321,600
Total liabilities and stockholders' (deficit) equity	1,573,510	622,255
Eliminating Entries [Member]
Current assets:
Federal and foreign income taxes receivable	(8,961)	(5,687)
State and local income taxes receivable	(996)
Intercompany receivables	(786,695)	(880,345)
Total current assets	(796,652)	(886,032)
Noncurrent assets:
Deferred income taxes, net	(49,557)	(39,787)
Investment in subsidiaries	(1,753,780)	(705,810)
Total assets	(2,599,989)	(1,631,629)
Current liabilities:
Intercompany payables	(786,695)	(880,345)
Federal and foreign income taxes payable	(8,961)	(5,687)
State and local income taxes payable	(996)
Total current liabilities	(796,652)	(886,032)
Noncurrent liabilities:
Deferred income taxes, net	(49,557)	(39,787)
Total liabilities	(846,209)	(925,819)
Total stockholders' (deficit) equity	(1,753,780)	(705,810)
Total liabilities and stockholders' (deficit) equity	$ (2,599,989)	$ (1,631,629)