Credit Facility - Additional Information (Detail) (USD $)	12 Months Ended	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Feb. 24, 2015
Line of Credit Facility [Line Items]
Date of credit agreement	Sep. 20, 2011
Date of credit amended	Dec. 23, 2014
Description of borrowing availability under credit facility	Available borrowings under the Credit Facility are limited to 85% of the net amount of eligible accounts receivable, plus 85% of the net amount of eligible unbilled accounts receivable, plus 80% of the net amount of eligible employee placement accounts, minus certain minimum availability reserve; provided, that the Firm may, subject to certain conditions, elect to increase the available borrowing limitation based on a percentage of the appraised fair market value of the Firm's corporate headquarters property and/or an additional percentage of net eligible accounts receivable, net eligible unbilled accounts receivable and net eligible employee placement accounts.
Interest rate terms	Outstanding borrowings under the Revolving Loan Amount bear interest at a rate of: (a) LIBOR plus an applicable margin based on various factors or (b) the higher of (1) the prime rate, (2) the federal funds rate plus 0.50% or (3) LIBOR plus 1.25%.
Percentage of accounts receivable	85.00%	85.00%
Percentage of unbilled accounts receivable	85.00%	85.00%
Percentage of employee placement accounts	80.00%	80.00%
Percentage of interest rate under revolving loan amount, Condition 1	1.25%	1.25%
Percentage of interest rate under revolving loan amount, Condition 2	0.50%	0.50%
Percentage of interest rate under revolving loan amount, Condition 3	0.125%	0.125%
Fixed charge coverage ratio required	1
Percentage of aggregate amount of the commitment	10.00%
Minimum availability under credit facility to avoid negative covenants	$ 11,000,000
Borrowing capacity under credit facility	39,600,000	39,600,000
Credit facility expiration date	Dec. 23, 2019
Outstanding under the Credit Facility	93,300,000	93,300,000	62,600,000
Amount outstanding under Credit Facility	93,300,000	93,300,000	62,600,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowing capacity under credit facility	170,000,000	170,000,000
Remaining credit facility under accordion option	50,000,000	50,000,000
Unused credit facility commitment fee percentage threshold	35.00%
Covenant limit on distributions and equity repurchases percent	12.50%
Covenant limit on distributions and equity repurchases	20,600,000	20,600,000
Maximum amount outstanding during period		93,300,000
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Sub-limit under credit facility for letters of credit	15,000,000.0
Subsequent Event [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Outstanding under the Credit Facility				97,000,000
Amount outstanding under Credit Facility				97,000,000
Credit facility remaining borrowing capacity				$ 39,700,000
Below Threshold [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Unused credit facility commitment fee percentage	0.35%
Above Threshold [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Unused credit facility commitment fee percentage	0.25%