Segment Disclosures - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 224,249	$ 207,723	$ 722,980	$ 660,198
Operating expenses	198,607	184,723	608,459	565,609
Gross margin	25,642	23,000	114,521	94,589
Corporate general & admin	10,279	7,979	30,300	25,979
Operating income (loss)	15,363	15,021	84,221	68,610
Other (expense) income:
Interest expense	(1,614)	(1,777)	(5,211)	(4,986)
Gain on sale of operations, net			663	45
Other income (expense), net	3,143	2,792	2,544	9,293
Total other income (expense), net	1,529	1,015	(2,004)	4,352
Income from continuing operations before income tax expense	16,892	16,036	82,217	72,962
Financial Services [Member]
Segment Reporting Information [Line Items]
Revenue	146,145		478,485
Benefits and Insurance Services [Member]
Segment Reporting Information [Line Items]
Revenue	70,069		220,152
National Practices [Member]
Segment Reporting Information [Line Items]
Revenue	8,035		24,343
Operating Segments [Member] | Financial Services [Member]
Segment Reporting Information [Line Items]
Revenue	146,145	130,305	478,485	421,529
Operating expenses	124,546	112,996	386,649	348,236
Gross margin	21,599	17,309	91,836	73,293
Operating income (loss)	21,599	17,309	91,836	73,293
Other (expense) income:
Other income (expense), net	(142)	79	106	122
Total other income (expense), net	(142)	79	106	122
Income from continuing operations before income tax expense	21,457	17,388	91,942	73,415
Operating Segments [Member] | Benefits and Insurance Services [Member]
Segment Reporting Information [Line Items]
Revenue	70,069	69,663	220,152	215,386
Operating expenses	59,399	59,155	181,697	179,174
Gross margin	10,670	10,508	38,455	36,212
Operating income (loss)	10,670	10,508	38,455	36,212
Other (expense) income:
Interest expense	(7)	(10)	(96)	(30)
Other income (expense), net	129	82	351	298
Total other income (expense), net	122	72	255	268
Income from continuing operations before income tax expense	10,792	10,580	38,710	36,480
Operating Segments [Member] | National Practices [Member]
Segment Reporting Information [Line Items]
Revenue	8,035	7,755	24,343	23,283
Operating expenses	7,514	7,109	22,356	21,351
Gross margin	521	646	1,987	1,932
Operating income (loss)	521	646	1,987	1,932
Other (expense) income:
Other income (expense), net				(9)
Total other income (expense), net				(9)
Income from continuing operations before income tax expense	521	646	1,987	1,923
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating expenses	7,148	5,463	17,757	16,848
Gross margin	(7,148)	(5,463)	(17,757)	(16,848)
Corporate general & admin	10,279	7,979	30,300	25,979
Operating income (loss)	(17,427)	(13,442)	(48,057)	(42,827)
Other (expense) income:
Interest expense	(1,607)	(1,767)	(5,115)	(4,956)
Gain on sale of operations, net			663	45
Other income (expense), net	3,156	2,631	2,087	8,882
Total other income (expense), net	1,549	864	(2,365)	3,971
Income from continuing operations before income tax expense	$ (15,878)	$ (12,578)	$ (50,422)	$ (38,856)