Stockholders' Equity (Details) (USD $)	1 Months Ended	3 Months Ended	25 Months Ended			3 Months Ended	1 Months Ended	3 Months Ended	1 Months Ended
	Jun. 30, 2012	Jun. 30, 2014	Jun. 30, 2014	Aug. 11, 2014 Subsequent Event	Jun. 30, 2014 2006 Equity Incentive Plan (2006 Plan)	Jun. 30, 2014 Nonvested stock units issued (NSUs) 2006 Equity Incentive Plan (2006 Plan)	Aug. 11, 2014 Nonvested stock units issued (NSUs) 2006 Equity Incentive Plan (2006 Plan) Subsequent Event	Jun. 30, 2014 Time-based equity award 2006 Equity Incentive Plan (2006 Plan)	Aug. 11, 2014 Time-based equity award 2006 Equity Incentive Plan (2006 Plan) Subsequent Event
Stockholders' equity
Common stock reserved for issuance (in shares)					6,000,000
Maximum number of shares that may be issued through the exercise of incentive stock options					4,500,000
Number of shares granted						35,000	105,000	19,000	4,000
Weighted average grant date fair value						$ 86.03	$ 82.85	$ 78.78	$ 82.85
NSUs granted that will vest at the end of each of the three years after the performance goals are achieved (as a percent)						33.30%
Award vesting period of the grants						3 years
Compensation cost not yet recognized		$ 4,300,000	$ 4,300,000	$ 9,000,000
Maximum stock repurchase amount approved by Board of Directors	200,000,000
Number of shares repurchased		0	2,765,000
Repurchase of common stock, payments			120,700,000
Average stock price of shares repurchased (in dollars per share)			$ 43.66
Remaining stock repurchase amount approved by Board of Directors			$ 79,300,000