Dividends Declared - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2013
Dividend Declared [Abstract]
Amount per share	$ 0.125	$ 0.125	$ 0.125	$ 0.375
Covenant revolving credit facility to maintain a minimum net worth to pay out returns of capital as dividends	$ 132			$ 132