Segment Disclosures - Summary of Segment Information (Parenthetical) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Financial Services [Member]
Segment Reporting Information [Line Items]
State payroll tax incentive associated with office relocation	$ 0.9
Benefits and Insurance Services [Member]
Segment Reporting Information [Line Items]
State payroll tax incentive associated with office relocation	0.6
Corporate and Other [Member]
Segment Reporting Information [Line Items]
State payroll tax incentive associated with office relocation	$ 0.1