Business Segments (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 73,992,000	$ 86,480,000	$ 241,404,000	$ 279,595,000
Cost of Sales	19,076,000	21,627,000	62,194,000	69,403,000
Selling, General and Administrative Expense	46,721,000	54,812,000	149,831,000	175,712,000
Depreciation and Amortization	2,256,000	2,692,000	7,332,000	7,912,000
Interest(net) and other	(906,000)	(529,000)	(2,489,000)	(898,000)
Income before income taxes	6,845,000	7,878,000	24,536,000	27,466,000
Segment Assets	115,339,000	148,396,000	115,339,000	148,396,000	132,650,000
Medifast Inc
Segment Reporting Information [Line Items]
Revenues	63,344,000	73,324,000	206,706,000	238,625,000
Cost of Sales	15,865,000	18,120,000	51,797,000	58,790,000
Selling, General and Administrative Expense	37,528,000	44,970,000	120,552,000	145,028,000
Depreciation and Amortization	1,853,000	1,939,000	5,808,000	5,583,000
Interest(net) and other	12,000	(306,000)	39,000	(228,000)
Income before income taxes	8,086,000	8,601,000	28,510,000	29,452,000
Segment Assets	68,724,000	91,370,000	68,724,000	91,370,000
MWCC & Wholesale
Segment Reporting Information [Line Items]
Revenues	10,648,000	13,156,000	34,698,000	40,970,000
Cost of Sales	3,211,000	3,507,000	10,397,000	10,613,000
Selling, General and Administrative Expense	6,258,000	8,434,000	23,116,000	26,058,000
Depreciation and Amortization	347,000	684,000	1,357,000	2,135,000
Interest(net) and other	12,000	3,000	(1,018,000)	7,000
Income before income taxes	820,000	528,000	846,000	2,157,000
Segment Assets	9,887,000	12,450,000	9,887,000	12,450,000
Other
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Cost of Sales	0	0	0	0
Selling, General and Administrative Expense	2,935,000	1,408,000	6,163,000	4,626,000
Depreciation and Amortization	56,000	69,000	167,000	194,000
Interest(net) and other	(930,000)	(226,000)	(1,510,000)	(677,000)
Income before income taxes	(2,061,000)	(1,251,000)	(4,820,000)	(4,143,000)
Segment Assets	$ 36,728,000	$ 44,576,000	$ 36,728,000	$ 44,576,000