Income Taxes - Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	$ 6,397	$ 5,127
Accrued employee benefits	4,195	3,420
Stock compensation	1,228	1,503
Accrued self-insurance	2,526	2,257
Acquisition costs	1,510	1,155
Net operating loss carry forward	927	873
Intangible asset impairment	49	55
Uncertain tax position-state tax portion	215	215
Deferred Tax Assets, Interest Expense	186	0
Other	121	61
Valuation allowance	(44)	(44)
Deferred tax assets	17,310	14,622
Deferred tax liabilities:
Amortization of intangible assets	(29,370)	(25,202)
Tax depreciation in excess of book depreciation	(7,994)	(7,171)
Prepaid expenses	(697)	(786)
Non-accrual experience accounting method	(1,459)	(1,223)
Deferred state tax receivable	0	(49)
Deferred tax liabilities	(39,520)	(34,431)
Net deferred tax liability	$ (22,210)	$ (19,809)