Summarized Consolidated Quarterly Information - Summarized Consolidated and Condensed Quarterly Financial Information (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]
Subscription revenue	$ 9,209,000	$ 8,780,000	$ 8,498,000	$ 8,234,000	$ 8,581,000	$ 7,827,000	$ 7,522,000	$ 7,298,000	$ 34,721,088	$ 31,228,644	$ 27,180,479
Income from continuing operations	16,304,000	705,000	522,000	402,000	6,519,000	860,000	498,000	136,000	17,933,431	8,013,330	4,861,385
Net (loss) income	$ 16,214,000	$ 649,000	$ 484,000	$ 250,000	$ 7,066,000	$ 666,000	$ 2,193,000	$ (14,209,000)	$ 17,596,942	$ (4,283,582)	$ 1,886,427
Per share amounts - basic:
Income from continuing operations	$ 1.49	$ 0.06	$ 0.05	$ 0.04	$ 0.61	$ 0.08	$ 0.05	$ 0.01	$ 1.65	$ 0.75	$ 0.46
Net (loss) income	$ 1.49	$ 0.06	$ 0.04	$ 0.02	$ 0.66	$ 0.06	$ 0.21	$ (1.34)	$ 1.62	$ (0.40)	$ 0.18
Per share amounts - diluted:
Income from continuing operations	$ 1.42	$ 0.05	$ 0.05	$ 0.04	$ 0.58	$ 0.08	$ 0.05	$ 0.01	$ 1.57	$ 0.73	$ 0.45
Net (loss) income	$ 1.41	$ 0.05	$ 0.04	$ 0.02	$ 0.63	$ 0.06	$ 0.20	$ (1.29)	$ 1.54	$ (0.39)	$ 0.17
Weighted average number of common shares outstanding:
Basic	10,909,000	10,908,000	10,892,000	10,828,000	10,728,000	10,703,000	10,686,000	10,624,000	10,884,533	10,685,333	10,569,805
Diluted	11,464,000	11,445,000	11,398,000	11,348,000	11,233,000	11,094,000	10,950,000	11,011,000	11,396,559	11,034,082	10,876,876