Earnings Per Share - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended					0 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Jul. 01, 2014	Dec. 31, 2013		Jul. 01, 2014 Fractional Shares [Member]
Earnings Per Share [Line Items]
Stock split, description	A three-for-two stock split
Percentage of stock dividend payable	50.00%
Record date for three for two stock split	Jun. 02, 2014
Stock split, payment date	Jul. 01, 2014
Cash paid to acquire fractional shares	$ 342,084	$ 342,820				$ 26
Common stock, shares issued	139,218,183		139,218,183	151,218,183	[1]
Common stock, par value	$ 1		$ 1	$ 1	[1]
Common stock, shares outstanding			131,031,843

[1] Derived from audited financial statements