Segment Information - Condensed Operating Data for Segments (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Subscription revenue	$ 10,726,000	$ 10,469,000	$ 10,194,000	$ 9,946,000	$ 9,209,000	$ 8,780,000	$ 8,498,000	$ 8,234,000	$ 41,335,155	$ 34,721,088	$ 31,228,644
Cost of sales of subscription revenue									8,037,019	6,973,772	6,616,931
Gross profit									33,298,136	27,747,316	24,611,713
Operating expenses:
Sales and marketing									10,235,349	8,349,544	7,643,303
Product development									3,472,875	3,121,729	2,485,168
General and administrative expenses									12,040,343	11,909,462	11,793,441
Total operating expenses									25,748,567	23,380,735	21,921,912
Other income (expenses):
Interest and other income									22,016	9,981	51,972
Interest expense									(113,200)	(113,200)	(155,443)
Total other income (expenses)									(91,184)	(103,219)	(103,471)
Income (loss) before income taxes and discontinued operations									7,458,385	4,263,362	2,586,330
(Loss) from discontinued operations, before income taxes									(951,000)	(566,000)	(12,297,000)
Reis Services [Member]
Segment Reporting Information [Line Items]
Subscription revenue									41,335,000	34,721,000	31,229,000
Cost of sales of subscription revenue									8,037,000	6,974,000	6,617,000
Gross profit									33,298,000	27,747,000	24,612,000
Operating expenses:
Sales and marketing									10,235,000	8,350,000	7,643,000
Product development									3,473,000	3,122,000	2,485,000
General and administrative expenses									7,940,000	6,989,000	6,696,000
Total operating expenses									21,648,000	18,461,000	16,824,000
Other income (expenses):
Interest and other income									22,000	10,000	50,000
Interest expense									(113,000)	(113,000)	(155,000)
Total other income (expenses)									(91,000)	(103,000)	(105,000)
Income (loss) before income taxes and discontinued operations									11,559,000	9,183,000	7,683,000
(Loss) from discontinued operations, before income taxes									0	0	0
Other [Member]
Segment Reporting Information [Line Items]
Subscription revenue									0	0	0
Cost of sales of subscription revenue									0	0	0
Gross profit									0	0	0
Operating expenses:
Sales and marketing									0	0	0
Product development									0	0	0
General and administrative expenses									4,101,000	4,920,000	5,098,000
Total operating expenses									4,101,000	4,920,000	5,098,000
Other income (expenses):
Interest and other income									0	0	1,000
Interest expense									0	0	0
Total other income (expenses)									0	0	1,000
Income (loss) before income taxes and discontinued operations									(4,101,000)	(4,920,000)	(5,097,000)
(Loss) from discontinued operations, before income taxes									(920,000)	(557,000)	(11,904,000)
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Subscription revenue									0	0	0
Cost of sales of subscription revenue									0	0	0
Gross profit									0	0	0
Operating expenses:
Sales and marketing									0	0	0
Product development									0	0	0
General and administrative expenses									0	0	0
Total operating expenses									0	0	0
Other income (expenses):
Interest and other income									0	0	0
Interest expense									0	0	0
Total other income (expenses)									0	0	0
Income (loss) before income taxes and discontinued operations									0	0	0
(Loss) from discontinued operations, before income taxes									$ (31,000)	$ (9,000)	$ (393,000)