Segment Disclosures - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenue	$ 277,455	$ 269,998
Operating expenses	199,827	215,496
Gross margin	77,628	54,502
Corporate general & administrative expenses	10,489	11,680
Operating income	67,139	42,822
Other (expense) income:
Interest expense	(1,119)	(1,401)
Gain on sale of operations, net	95	497
Other (expense) income, net	(15,800)	9,260
Total other (expense) income, net	(16,824)	8,356
Income from continuing operations before income tax expense	50,315	51,178
Financial Services [Member]
Segment Reporting Information [Line Items]
Revenue	188,777	185,144
Benefits and Insurance Services [Member]
Segment Reporting Information [Line Items]
Revenue	79,612	76,255
National Practices [Member]
Segment Reporting Information [Line Items]
Revenue	9,066	8,599
Operating Segments [Member] | Financial Services [Member]
Segment Reporting Information [Line Items]
Revenue	188,777	185,144
Operating expenses	138,598	134,458
Gross margin	50,179	50,686
Operating income	50,179	50,686
Other (expense) income:
Gain on sale of operations, net	40	497
Other (expense) income, net	19	(136)
Total other (expense) income, net	59	361
Income from continuing operations before income tax expense	50,238	51,047
Operating Segments [Member] | Benefits and Insurance Services [Member]
Segment Reporting Information [Line Items]
Revenue	79,612	76,255
Operating expenses	65,223	61,371
Gross margin	14,389	14,884
Operating income	14,389	14,884
Other (expense) income:
Interest expense	(11)	(10)
Gain on sale of operations, net	55
Other (expense) income, net	96	21
Total other (expense) income, net	140	11
Income from continuing operations before income tax expense	14,529	14,895
Operating Segments [Member] | National Practices [Member]
Segment Reporting Information [Line Items]
Revenue	9,066	8,599
Operating expenses	8,283	8,000
Gross margin	783	599
Operating income	783	599
Other (expense) income:
Other (expense) income, net	1
Total other (expense) income, net	1
Income from continuing operations before income tax expense	784	599
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating expenses	(12,277)	11,667
Gross margin	12,277	(11,667)
Corporate general & administrative expenses	10,489	11,680
Operating income	1,788	(23,347)
Other (expense) income:
Interest expense	(1,108)	(1,391)
Other (expense) income, net	(15,916)	9,375
Total other (expense) income, net	(17,024)	7,984
Income from continuing operations before income tax expense	$ (15,236)	$ (15,363)