Stockholders' Equity - Stock Options Granted (Details)	99 Months Ended
	Jun. 30, 2016 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	6,413,660
Options Outstanding (in shares)	4,116,511
Options Exercisable (in shares)	1,238,025
April 19, 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	845,440
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 46.00
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 45.74
Options Outstanding (in shares)	819,466
Options Exercisable (in shares)	0
April 21, 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	893,220
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 42.00
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 41.26
Options Outstanding (in shares)	775,020
Options Exercisable (in shares)	0
April 22, 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	955,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 56.00
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 50.53
Options Outstanding (in shares)	642,500
Options Exercisable (in shares)	10,000
April 16, 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	205,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 54.00
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 49.25
Options Outstanding (in shares)	115,000
Options Exercisable (in shares)	2,500
April 17, 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	1,235,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 54.00
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 49.01
Options Outstanding (in shares)	1,015,250
Options Exercisable (in shares)	617,500
April 19, 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	410,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 35.00
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 31.78
Options Outstanding (in shares)	200,800
Options Exercisable (in shares)	163,300
April 20, 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	530,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 30.00
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 27.13
Options Outstanding (in shares)	181,725
Options Exercisable (in shares)	121,725
April 21, 2009 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	790,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 27.00
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 17.61
Options Outstanding (in shares)	252,650
Options Exercisable (in shares)	208,900
April 15, 2008 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Granted (in shares)	550,000
Option Exercise (Strike) Price (in dollars per share) | $ / shares	$ 27.00
Closing Stock Price on Date of Grant (in dollars per share) | $ / shares	$ 24.35
Options Outstanding (in shares)	114,100
Options Exercisable (in shares)	114,100