Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	13 Months Ended		0 Months Ended	3 Months Ended	9 Months Ended		12 Months Ended	3 Months Ended	9 Months Ended
	Aug. 31, 2013	Sep. 30, 2013	Jun. 07, 2013 Ronald Rubin's [Member]	Sep. 30, 2012 Ronald Rubin's [Member]	Sep. 30, 2013 Ronald Rubin's [Member]	Sep. 30, 2012 Ronald Rubin's [Member]	Dec. 31, 2012 Ronald Rubin's [Member]	Sep. 30, 2012 Edward Glickman [Member]	Sep. 30, 2012 Edward Glickman [Member]
Unaccrued Contractual Commitments and Employee Separation Expenses [Line Items]
Unaccrued Contractual And Other Commitments		$ 10.1
Employee Separation Expense, Incurred to Date					4.5
Provision for cash separation agreement	0.4			1.1	1.9	1.4	2.6	3.5	4.0
Restricted shares granted under Equity Incentive Plan					16,000
Restricted shares granted, fair value					0.3
Restricted shares granted, fair value per share					$ 18.28
Founder's retirement payment			$ 3.5