Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2016

Stockholders' Equity Note [Abstract]

Changes To Equity

Shares of our common stock outstanding and activity for the years ended December 31, 2016, 2015 and 2014 are presented below:

	Years Ended December 31,
	2016		2015		2014
Common shares outstanding at January 1	180,234,388		196,086,090		198,830,351
Issuance of restricted stock, excluding restricted stock with performance feature	870,378		447,534		376,622
Vesting of performance units	76,404		136,896		416,111
Vesting of restricted stock with performance feature	40,294		43,774		77,430
Forfeitures of restricted stock	(16,795	)	(51,332	)	(76,107	)
Purchase of treasury stock (1)	(3,859,403	)	(16,428,574	)	(3,538,317	)
Common shares outstanding at December 31	177,345,266		180,234,388		196,086,090

(1) Includes 147,922, 151,967 and 279,680 shares, respectively, withheld under the terms of stock-based compensation agreements to provide funds for the payment of payroll and income taxes due at the vesting of share-based awards, as well as other stock repurchases under separate authority from our Board of Directors.