Segment Information - Additional Information (Detail) - Reis Services [Member]		6 Months Ended
	Jul. 31, 2018 USD ($)	Jun. 30, 2018 Subscriber	Jun. 30, 2017
Segment Reporting Information [Line Items]
Percentage of Reis Service's revenue by major customer		5.70%	3.30%
Number of subscribers contributing largest share among accounts receivable		16
Aggregate percentage of subscribers contributing largest share among accounts receivable		68.90%
Number of subscribers individually accounted for more than 4% of accounts receivable		3
Percentage of deferred revenue by major subscriber		13.40%
Subsequent Event [Member]
Segment Reporting Information [Line Items]
Payments received against accounts receivable | $	$ 4,903,000
Percentage collected from trade accounts receivable	48.30%
Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Segment Reporting Information [Line Items]
Percentage of aggregate revenue under contract		7.30%
Maximum [Member]
Segment Reporting Information [Line Items]
Percentage of Reis Service's accounts receivable by major subscriber		30.80%