Summary of Significant Accounting Policies (Detail 2)	36 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Share-based compensation
Options granted (in shares)	0
Common Stock Held in Treasury, at Cost
Number of shares of common stock held in treasury	18,000,756	18,000,756	16,005,500
Stock options
Share-based compensation
Options granted (in shares)		0