Business Segments - Summary of Revenues, Net Income and Long-Lived Assets (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Revenue	$ 1,105,888,574		$ 942,980,596		$ 879,696,657
Net income	8,482,239		16,940,194		23,626,643
Long-lived assets	193,946,284		201,773,921		196,626,313
United States [Member]
Revenue	1,091,777,568	[1]	920,341,603	[1]	857,507,678	[1]
Net income	11,044,991	[1]	16,924,287	[1]	23,321,638	[1]
Long-lived assets	190,415,521	[1]	195,776,953	[1]	189,961,245	[1]
Canada [Member]
Revenue	14,111,006		22,638,993		22,188,979
Net income	(2,562,752)		15,907		305,005
Long-lived assets	$ 3,530,763		$ 5,996,968		$ 6,665,068

[1] The Social Services and NET Services operating segments, on an aggregate basis, derived approximately 12.8%, 12.2% and 9.7% of the Company's consolidated revenue from the State of Virginia's Department of Medical Assistance Services for the years ended December 31, 2010, 2011 and 2012, respectively. Additionally, both segments, on an aggregate basis, derived approximately 11.0% and 10.3% of the Company's consolidated revenue from the State of New Jersey for the years ended December 31, 2011 and 2012, respectively.