Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2017

Stockholders' Equity Note [Abstract]

Schedule of Dividends Paid Previously or Declared

The following table presents the dividends either paid previously or declared by our board of directors for future payment on a per share basis:



	2017		2016
First quarter	$	0.32	0.30
Second quarter	0.32		0.30
Third quarter			0.30
Fourth quarter			0.30
Total	$	0.64	1.20

Stock Options Granted

The following tables summarize the details of options granted under our stock option plan that were still outstanding as of March 31, 2017, and the assumptions used to value these grants. All such grants were effective at the close of business on the date of grant.



	Options Granted	Option Exercise (Strike) Price		Closing Stock Price on Date of Grant		March 31, 2017
Date of Grant	Options Granted	Option Exercise (Strike) Price		Closing Stock Price on Date of Grant		Options Outstanding	Options Exercisable
January 3, 2017	764,789	$	47.00	$	46.95	751,813	—
April 19, 2016	845,440	$	46.00	$	45.74	777,409	—
April 21, 2015	893,220	$	42.00	$	41.26	718,122	—
April 22, 2014	955,000	$	56.00	$	50.53	587,500	116,250
April 16, 2013	205,000	$	54.00	$	49.25	115,000	3,500
April 17, 2012	1,235,000	$	54.00	$	49.01	968,250	673,250
April 19, 2011	410,000	$	35.00	$	31.78	74,800	37,300
April 20, 2010	530,000	$	30.00	$	27.13	115,300	62,800
April 21, 2009	790,000	$	27.00	$	17.61	227,900	185,400
April 15, 2008	550,000	$	27.00	$	24.35	4,500	4,500
Total	7,178,449					4,340,594	1,083,000

Fair Value Assumptions for Options Granted



Date of Grant	Risk-free Interest Rate		Expected Life of Option in Years	Expected Dividend Yield		Expected Stock Volatility		Estimated Fair Value of Stock Option
January 3, 2017	1.9	%	5.00	2.6	%	24.49	%	$	8.40
April 19, 2016	1.3	%	5.00	2.6	%	26.34	%	$	8.18
April 21, 2015	1.3	%	5.00	2.7	%	26.84	%	$	7.35
April 22, 2014	1.8	%	5.00	2.0	%	28.55	%	$	9.57
April 16, 2013	0.7	%	5.00	1.6	%	37.42	%	$	12.66
April 17, 2012	0.9	%	5.00	1.4	%	39.25	%	$	13.69
April 19, 2011	2.1	%	5.00	1.6	%	39.33	%	$	11.20
April 20, 2010	2.6	%	5.00	1.5	%	39.10	%	$	8.14
April 21, 2009	1.9	%	5.00	1.0	%	38.80	%	$	3.64
April 15, 2008	2.7	%	5.00	1.0	%	30.93	%	$	7.75

Reconciliation of Denominators used in Computation of Basic and Diluted Earnings Per Share

The following tables present a reconciliation of the denominators used in the computation of basic and diluted earnings per share and a summary of the options to purchase shares of common stock which were excluded from the diluted earnings per share calculation because they were anti-dilutive:



	Three-month Period
Reconciliation	2017	2016
Basic weighted average shares outstanding	289,242,447	288,808,019
Weighted shares assumed upon exercise of stock options	213,494	315,584
Diluted weighted average shares outstanding	289,455,941	289,123,603

Anti-Dilutive Options Excluded

Three-month Period

Summary of Anti-dilutive Options Excluded

Options to purchase shares of common stock

Weighted average exercise price of options