Significant Items Making up Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Components Of Deferred Tax Assets And Liabilities [Abstract]
Allowances not currently deductible for tax purposes	$ 2,844	$ 3,481
Net operating loss carryforwards	64,741	62,779
Accrued and other	7,149	8,781
Deferred Tax Assets, Gross, Total	74,734	75,041
Less valuation allowance	(71,023)	(70,478)
Deferred Tax Assets, Net of Valuation Allowance, Total	3,711	4,563
Depreciation and amortization	(2,220)	(2,774)
Other	(1,491)	(1,789)
Deferred Tax Liabilities, Gross, Total	$ (3,711)	$ (4,563)