Segment Disclosures - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Revenue	$ 300,730	$ 277,455
Operating expenses	223,971	199,827
Gross margin	76,759	77,628
Corporate general and administrative expenses	14,483	10,489
Operating income	62,276	67,139
Other income (expense):
Interest expense	(877)	(1,119)
Gain on sale of operations, net	0	95
Other income (expense), net	4,789	(15,800)
Total other income (expense), net	3,912	(16,824)
Income from continuing operations before income tax    expense	66,188	50,315
Financial Services
Segment Reporting Information [Line Items]
Revenue	204,149	188,777
Benefits & Insurance
Segment Reporting Information [Line Items]
Revenue	87,239	79,612
National Practices
Segment Reporting Information [Line Items]
Revenue	9,342	9,066
Operating segments | Financial Services
Segment Reporting Information [Line Items]
Revenue	204,149	188,777
Operating expenses	141,746	138,598
Gross margin	62,403	50,179
Corporate general and administrative expenses	0	0
Operating income	62,403	50,179
Other income (expense):
Interest expense	0	0
Gain on sale of operations, net		40
Other income (expense), net	98	19
Total other income (expense), net	98	59
Income from continuing operations before income tax    expense	62,501	50,238
Operating segments | Benefits & Insurance
Segment Reporting Information [Line Items]
Revenue	87,239	79,612
Operating expenses	66,933	65,223
Gross margin	20,306	14,389
Corporate general and administrative expenses	0	0
Operating income	20,306	14,389
Other income (expense):
Interest expense	0	(11)
Gain on sale of operations, net		55
Other income (expense), net	174	96
Total other income (expense), net	174	140
Income from continuing operations before income tax    expense	20,480	14,529
Operating segments | National Practices
Segment Reporting Information [Line Items]
Revenue	9,342	9,066
Operating expenses	8,541	8,283
Gross margin	801	783
Corporate general and administrative expenses	0	0
Operating income	801	783
Other income (expense):
Interest expense	0	0
Gain on sale of operations, net		0
Other income (expense), net	0	1
Total other income (expense), net	0	1
Income from continuing operations before income tax    expense	801	784
Corporate and Other
Segment Reporting Information [Line Items]
Revenue	0	0
Operating expenses	6,751	(12,277)
Gross margin	(6,751)	12,277
Corporate general and administrative expenses	14,483	10,489
Operating income	(21,234)	1,788
Other income (expense):
Interest expense	(877)	(1,108)
Gain on sale of operations, net		0
Other income (expense), net	4,517	(15,916)
Total other income (expense), net	3,640	(17,024)
Income from continuing operations before income tax    expense	$ (17,594)	$ (15,236)