Noncontrolling Interest - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended
	Oct. 31, 2009	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Noncontrolling Interest [Line Items]
Subsidiary common stock, shares issued	1,437,500,000
Percentage of issuance of common stock	27.70%
Net income attributable to noncontrolling interest		$ 62,931	$ 61,229	$ 132,112	$ 119,074