XML 44 R34.htm IDEA: XBRL DOCUMENT

Income taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2011
Income Taxes [Line Items]
Non-cash charge for state deferred income taxes	$ 0.7

The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to changes in the income tax rates under enacted tax laws in the period.

+ References+ Details