Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Nature of Business and Significant Accounting Policies [Line Items]
Maximum scheduled period to commence employment for search revenue recognition	30 days
Typical contingency period for occurrence of fallouts	90 days
Minimum likelihood of being realized upon settlement of uncertain tax positions	50.00%
Accounts receivable reserves as percentage of gross accounts receivable	1.00%	1.10%
Short-term office lease, maximum term	1 year
Economic burden for worker's compensation claim per occurrence	$ 250,000
Health insurance maximum risk of loss liability per employee insurance plan (up to)	350,000
Health insurance maximum aggregate amount of risk of loss liability for employee insurance plans (up to)	$ 450,000
Defined benefit plan amortization threshold percentage	10.00%
Common stock equivalents (in shares)	175	280	216
Antidilutive common stock equivalents (in shares)	0	0	0
Percent of timing of revenue recognition not impacted by new guidance	95.00%
Minimum
Nature of Business and Significant Accounting Policies [Line Items]
Term of office leases	3 years
Cost allocation period for definite-lived intangible assets	1 year
Maximum
Nature of Business and Significant Accounting Policies [Line Items]
Term of office leases	5 years
Cost allocation period for definite-lived intangible assets	15 years
Leasehold Improvements | Minimum
Nature of Business and Significant Accounting Policies [Line Items]
Amortization period	3 years
Leasehold Improvements | Maximum
Nature of Business and Significant Accounting Policies [Line Items]
Amortization period	5 years
Computers and Software | Minimum
Nature of Business and Significant Accounting Policies [Line Items]
Amortization period	1 year
Computers and Software | Maximum
Nature of Business and Significant Accounting Policies [Line Items]
Amortization period	7 years
Government Solutions
Nature of Business and Significant Accounting Policies [Line Items]
Percentage of consolidated revenue	7.00%
Time and material contracts revenue as percentage of aggregate segment revenue	62.00%
Fixed-price contracts revenue recognized as percentage of aggregate segment revenue	22.00%
Product contracts revenue recognized as percentage of aggregate segment revenue	16.00%