Taxes - Changes in the Reserve for Income Taxes, Excluding Interest and Penalties (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Tax Credit Carryforward [Line Items]
Beginning Balance of reserve for income taxes	$ 4,148	$ 4,181
Gross amounts of increases in unrecognized tax benefits as a result of tax positions taken in prior periods	43	7
Gross amounts of increases in unrecognized tax benefits as a result of tax positions taken in the current period	642	937
Gross amounts of decreases in unrecognized tax benefits relating to settlements with taxing authorities	(424)	(192)
Gross amounts of decreases in unrecognized tax benefits as a result of the expiration of the applicable statutes of limitations	(385)	(785)
Ending balance of reserve for income taxes	$ 4,024	$ 4,148

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The gross amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns as of the balance sheet date.

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-Publisher FASB

-Name Accounting Standards Codification

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The gross amount of decreases in unrecognized tax benefits resulting from settlements with taxing authorities.

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The gross amount of increases in unrecognized tax benefits resulting from tax positions that have been or will be taken in the tax return for the current period, excluding amounts pertaining to examined tax returns.

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The gross amount of decreases in unrecognized tax benefits resulting from lapses of the applicable statutes of limitations.

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