Condensed Consolidated Financial Information for Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Condensed Consolidating Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Revenues	$ 403,323	$ 346,501
Expenses:
Cost of revenues (exclusive of items shown separately below)	164,449	133,330
Selling, general and administrative	59,028	53,979
Depreciation and amortization of fixed assets	15,214	11,644
Amortization of intangible assets	17,207	8,587
Total expenses	255,898	207,540
Operating income	147,425	138,961
Other income (expense):
Interest expense	(20,090)	(16,385)
Investment income	48	105
Realized (loss) gain on available-for-sale securities, net	(193)	330
Total other (expense) income, net	(20,235)	(15,950)
(Loss) income before equity in net income of subsidiaries and income taxes	127,190	123,011
Provision for income taxes	(46,679)	(48,410)
Net income	80,511	74,601	329,142
Verisk Analytics, Inc. [Member]
Other income (expense):
Interest expense	(13,637)	(9,869)
Investment income		18
Total other (expense) income, net	(13,637)	(9,851)
(Loss) income before equity in net income of subsidiaries and income taxes	(13,637)	(9,851)
Equity in net income of subsidiaries	89,135	80,836
Provision for income taxes	5,013	3,616
Net income	80,511	74,601
Guarantor Subsidiaries [Member]
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Revenues	329,026	307,099
Expenses:
Cost of revenues (exclusive of items shown separately below)	126,568	116,339
Selling, general and administrative	46,897	43,337
Depreciation and amortization of fixed assets	12,093	9,551
Amortization of intangible assets	4,680	4,928
Total expenses	190,238	174,155
Operating income	138,788	132,944
Other income (expense):
Interest expense	(6,448)	(6,507)
Investment income		74
Realized (loss) gain on available-for-sale securities, net	(193)	330
Total other (expense) income, net	(6,641)	(6,103)
(Loss) income before equity in net income of subsidiaries and income taxes	132,147	126,841
Equity in net income of subsidiaries	1,273	286
Provision for income taxes	(46,492)	(48,320)
Net income	86,928	78,807
Non-Guarantor Subsidiaries [Member]
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Revenues	79,220	43,601
Expenses:
Cost of revenues (exclusive of items shown separately below)	40,215	19,372
Selling, general and administrative	14,720	12,460
Depreciation and amortization of fixed assets	3,121	2,093
Amortization of intangible assets	12,527	3,659
Total expenses	70,583	37,584
Operating income	8,637	6,017
Other income (expense):
Interest expense	(5)	(9)
Investment income	48	13
Total other (expense) income, net	43	4
(Loss) income before equity in net income of subsidiaries and income taxes	8,680	6,021
Provision for income taxes	(5,200)	(3,706)
Net income	3,480	2,315
Eliminating Entries [Member]
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Revenues	(4,923)	(4,199)
Expenses:
Cost of revenues (exclusive of items shown separately below)	(2,334)	(2,381)
Selling, general and administrative	(2,589)	(1,818)
Total expenses	(4,923)	(4,199)
Other income (expense):
Equity in net income of subsidiaries	(90,408)	(81,122)
Net income	$ (90,408)	$ (81,122)