Goodwill and Other Intangible Assets - Carrying Amount of Amortizable Intangible Assets and Related Accumulated Amortization (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (in years)	9 years 8 months 14 days
Gross Carrying Amount	$ 45,975	$ 42,893
Accumulated Amortization	(25,577)	(24,206)
Net Carrying Amount	$ 20,398	18,687
Client Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (in years)	8 years 3 months 18 days
Gross Carrying Amount	$ 28,546	25,414
Accumulated Amortization	(18,332)	(17,550)
Net Carrying Amount	$ 10,214	7,864
Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (in years)	15 years
Gross Carrying Amount	$ 9,215	9,251
Accumulated Amortization	(3,648)	(3,416)
Net Carrying Amount	$ 5,567	5,835
Software [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (in years)	7 years
Gross Carrying Amount	$ 7,200	7,200
Accumulated Amortization	(3,343)	(3,086)
Net Carrying Amount	$ 3,857	4,114
Non-compete [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (in years)	5 years
Gross Carrying Amount	$ 583	586
Accumulated Amortization	(182)	(117)
Net Carrying Amount	$ 401	469
Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Life (in years)	3 years
Gross Carrying Amount	$ 431	442
Accumulated Amortization	(72)	(37)
Net Carrying Amount	$ 359	$ 405