Segment Disclosures - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 232,641	$ 232,641	$ 211,016	$ 498,731	$ 452,475
Operating expenses	205,102		188,120	409,852	380,886
Gross margin	27,539		22,896	88,879	71,589
Corporate general & admin	9,993		9,232	20,021	18,000
Operating income (loss)	17,546		13,664	68,858	53,589
Other (expense) income:
Interest expense	(1,817)		(1,692)	(3,597)	(3,209)
Other (expense) income, net	630		3,764	(599)	6,501
Gain on sale of operations, net			23	663	45
Total other (expense) income, net	(1,187)		2,095	(3,533)	3,337
Income from continuing operations before income tax expense	16,359		15,759	65,325	56,926
Financial Services [Member]
Segment Reporting Information [Line Items]
Revenue		151,737		332,340
Benefits and Insurance Services [Member]
Segment Reporting Information [Line Items]
Revenue		72,753		150,083
National Practices [Member]
Segment Reporting Information [Line Items]
Revenue		$ 8,151		16,308
Operating Segments [Member] | Financial Services [Member]
Segment Reporting Information [Line Items]
Revenue	151,737		132,591	332,340	291,224
Operating expenses	129,070		115,851	262,103	235,240
Gross margin	22,667		16,740	70,237	55,984
Operating income (loss)	22,667		16,740	70,237	55,984
Other (expense) income:
Other (expense) income, net	(17)		28	248	43
Total other (expense) income, net	(17)		28	248	43
Income from continuing operations before income tax expense	22,650		16,768	70,485	56,027
Operating Segments [Member] | Benefits and Insurance Services [Member]
Segment Reporting Information [Line Items]
Revenue	72,753		70,559	150,083	145,723
Operating expenses	61,165		59,877	122,298	120,019
Gross margin	11,588		10,682	27,785	25,704
Operating income (loss)	11,588		10,682	27,785	25,704
Other (expense) income:
Interest expense	(15)		(9)	(89)	(20)
Other (expense) income, net	30		120	222	216
Total other (expense) income, net	15		111	133	196
Income from continuing operations before income tax expense	11,603		10,793	27,918	25,900
Operating Segments [Member] | National Practices [Member]
Segment Reporting Information [Line Items]
Revenue	8,151		7,866	16,308	15,528
Operating expenses	7,567		7,235	14,842	14,242
Gross margin	584		631	1,466	1,286
Operating income (loss)	584		631	1,466	1,286
Other (expense) income:
Other (expense) income, net			(9)		(9)
Total other (expense) income, net			(9)		(9)
Income from continuing operations before income tax expense	584		622	1,466	1,277
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating expenses	7,300		5,157	10,609	11,385
Gross margin	(7,300)		(5,157)	(10,609)	(11,385)
Corporate general & admin	9,993		9,232	20,021	18,000
Operating income (loss)	(17,293)		(14,389)	(30,630)	(29,385)
Other (expense) income:
Interest expense	(1,802)		(1,683)	(3,508)	(3,189)
Other (expense) income, net	617		3,625	(1,069)	6,251
Gain on sale of operations, net			23	663	45
Total other (expense) income, net	(1,185)		1,965	(3,914)	3,107
Income from continuing operations before income tax expense	$ (18,478)		$ (12,424)	$ (34,544)	$ (26,278)