Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Revenue	$ 799,832	$ 750,422		$ 719,483
Operating expenses	697,726	652,391	[1]	629,804
Gross margin	102,106	98,031		89,679
Corporate general and administrative expenses	36,319	32,527	[1]	34,183
Operating income (loss)	65,787	65,504		55,496
Other income (expense):
Interest expense	(6,593)	(8,902)		(13,124)
Gain on sale of operations, net	855	84		1,303
Other income, net	6,957	1,146	[1]	6,893
Total other income (expense), net	1,219	(7,672)		(4,928)
Income from continuing operations before income tax expense	67,006	57,832		50,568
Income tax expense	26,399	22,829		20,154
Income (loss) from continuing operations	40,607	35,003		30,414
Loss from operations of discontinued operations, net of tax	(542)	(2,323)		(754)
Gain on disposal of discontinued operations, net of tax		1,427		99
Net income (loss)	$ 40,065	$ 34,107		$ 29,759
Basic:
Continuing operations	$ 0.78	$ 0.70		$ 0.63
Discontinued operations	(0.01)	(0.01)		(0.01)
Net income	0.77	0.69		0.62
Diluted:
Continuing operations	0.76	0.66		0.59
Discontinued operations	(0.01)	(0.01)		(0.01)
Net income	$ 0.75	$ 0.65		$ 0.58
Basic weighted average common shares outstanding	52,321	50,280		48,343
Diluted weighted average common shares outstanding	53,513	52,693		51,487
Comprehensive income:
Net income	$ 40,065	$ 34,107		$ 29,759
Other comprehensive income:
Net unrealized loss on available-for-sale securities, net of income tax benefit of $16, $77 and $74	(23)	(114)		(117)
Net unrealized gain on interest rate swaps, net of income tax expense of $107, $135 and $121	182	230		206
Foreign currency translation	(30)	(54)		(59)
Total other comprehensive income	129	62		30
Total comprehensive income	$ 40,194	$ 34,169		$ 29,789

[1] “Operating expenses” under the Financial Services and Benefits and Insurance Services practice groups include a reduction of $0.9 million and $0.6 million related to a state payroll tax incentive associated with an office relocation. “Corporate general and administrative expenses” include a reduction of less than $0.1 million related to the office relocation as discussed above. The reductions was recorded in “Other (expense) income, net” in 2015 but was reclassified to “Operating expenses” and “Corporate general and administrative expenses” to align the incentives with the expenses associated with the office relocation. The reclassification had no impact on “Income from continuing operations” or diluted earnings per share from continuing operations.