Goodwill and Intangible Assets - Components of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Apr. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 33,331	$ 33,367	$ 33,005
Less accumulated amortization	(24,079)	(21,559)	(19,585)
Intangible assets, net	9,252	11,808	13,420
Covenants Not-to-Compete [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	17,266	17,296	17,245
Less accumulated amortization	(16,198)	(15,730)	(15,363)
Intangible assets, net	1,068	1,566	1,882
Client Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	16,065	16,071	15,760
Less accumulated amortization	(7,881)	(5,829)	(4,222)
Intangible assets, net	$ 8,184	$ 10,242	$ 11,538

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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