Discontinued Operations - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 21,200,000	$ 14,500,000
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	9,400,000
Income (Loss) from Continuing Operations Attributable to Noncontrolling Interest	825,000	691,000
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest	$ 0	$ 488,000