Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2010
Income Taxes [Line Items]
Reduction in net deferred tax assets	$ 22.7	$ 233.7
Amortization period for tax basis intangibles, years	15 years
Taxable loss of partnership		56.8		81.4
Taxable loss carried back and utilized against prior year taxable income	8.8
Taxable loss, utilized against taxable income	54.6		74.9
Carryforward period for tax basis intangibles, years	20 years
Unrecognized tax benefits that if recognized would affect the annual effective rate	18.9		26.8
Interest expense accrued	1.0	1.5	5.8
Accrued Penalties	$ 0	$ 0	$ 0.5