Stockholders' Equity (Deficit) (Tables)

12 Months Ended

Dec. 31, 2017

Stockholders' Equity Note [Abstract]

Schedule of Stockholders Equity

The following table summarizes the changes in shares of Common Stock outstanding and Treasury Stock:

	Common Stock Outstanding		Treasury Stock
Balance at December 31, 2014	201,027,964		122,309,948
Repurchases of common stock	(6,476,796	)	6,476,796
Issuance of common stock	943,686		(943,686	)
Conversions to common stock	26,354		(26,354	)
Balance at December 31, 2015	195,521,208		127,816,704
Repurchases of common stock	(10,633,235	)	10,633,235
Issuance of common stock	767,060		(767,060	)
Conversions to common stock	13,685		(13,685	)
Balance at December 31, 2016	185,668,718		137,669,194
Issuance of common stock	881,480		(881,480	)
Conversions to common stock	53,540		(53,540	)
Balance at December 31, 2017	186,603,738		136,734,174