Segment Disclosures - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Revenue	$ 269,998	$ 266,090
Operating expenses	215,496	204,750
Gross margin	54,502	61,340
Corporate general & administrative expenses	11,680	10,028
Operating income	42,822	51,312
Other income (expense):
Interest expense	(1,401)	(1,780)
Gain on sale of operations, net	497	663
Other (expense) income, net	9,260	(1,229)
Total other income (expense), net	8,356	(2,346)
Income from continuing operations before income tax expense	51,178	48,966
Operating Segments [Member] | Financial Services [Member]
Segment Reporting Information [Line Items]
Revenue	185,144	180,603
Operating expenses	134,458	133,033
Gross margin	50,686	47,570
Operating income	50,686	47,570
Other income (expense):
Gain on sale of operations, net	497
Other (expense) income, net	(136)	265
Total other income (expense), net	361	265
Income from continuing operations before income tax expense	51,047	47,835
Operating Segments [Member] | Benefits and Insurance Services [Member]
Segment Reporting Information [Line Items]
Revenue	76,255	77,330
Operating expenses	61,371	61,133
Gross margin	14,884	16,197
Operating income	14,884	16,197
Other income (expense):
Interest expense	(10)	(75)
Gain on sale of operations, net		663
Other (expense) income, net	21	193
Total other income (expense), net	11	781
Income from continuing operations before income tax expense	14,895	16,978
Operating Segments [Member] | National Practices [Member]
Segment Reporting Information [Line Items]
Revenue	8,599	8,157
Operating expenses	8,000	7,275
Gross margin	599	882
Operating income	599	882
Other income (expense):
Income from continuing operations before income tax expense	599	882
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating expenses	11,667	3,309
Gross margin	(11,667)	(3,309)
Corporate general & administrative expenses	11,680	10,028
Operating income	(23,347)	(13,337)
Other income (expense):
Interest expense	(1,391)	(1,705)
Other (expense) income, net	9,375	(1,687)
Total other income (expense), net	7,984	(3,392)
Income from continuing operations before income tax expense	$ (15,363)	$ (16,729)