Stock-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				12 Months Ended	3 Months Ended		6 Months Ended			3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Stock Options	Mar. 31, 2013 Stock Options	Dec. 31, 2013 Stock Options	Mar. 31, 2014 Restricted Shares	Jun. 30, 2013 Restricted Shares	Jun. 30, 2013 Restricted Shares	Mar. 31, 2014 2000 Employee Option Plan	Mar. 31, 2014 2009 Employee Option Plan	Mar. 31, 2014 2000 Employee Option Plan and 2009 Employee Option Plan	Mar. 31, 2014 2004 Directors Option Plan	Mar. 31, 2014 2012 Directors Restricted Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award
Number of additional stock options that can be granted (in shares)									0
Shares available for the granting of additional stock options										2,375,110		70,000	95,131
Options ratable vesting period											5 years	3 years
Options exercisable period											10 years	10 years
Number of additional stock options expected to be granted (in shares)												0
Expense incurred for stock-based compensation plans (in dollars)	$ 9,276	$ 8,283
Expense incurred for stock-based compensation plans, net of tax (in dollars)	6,804	6,031
Stock option activity
Options outstanding at the beginning of the period (in shares)			13,422,226
Options granted (in shares)			32,500
Options exercised (in shares)			(314,966)
Options forfeited (in shares)			(51,460)
Options outstanding at the end of the period (in shares)			13,088,300		13,422,226
Vested and non-vested options expected to vest at the end of the period (in shares)			11,928,448
Exercisable at the end of the period (in shares)			5,097,339
Weighted Average Exercise Price
Weighted average exercise price, options outstanding at the beginning of the period (in dollars per share)			$ 51.80
Weighted average exercise price, options granted (in dollars per share)			$ 89.13
Weighted average exercise price, options exercised (in dollars per share)			$ 40.41
Weighted average exercise price, options forfeited (in dollars per share)			$ 59.80
Weighted average exercise price, options outstanding at the end of the period (in dollars per share)			$ 52.14		$ 51.80
Weighted average exercise price, vested and non-vested options expected to vest (in dollars per share)			$ 51.50
Weighted average exercise price, exercisable (in dollars per share)			$ 41.15
Weighted Average Remaining Contractual Term
Weighted average remaining contractual term of options outstanding			6 years 10 months 20 days		7 years 29 days
Weighted average remaining contractual term of options vested options and non-vested expected to vest			6 years 9 months 18 days
Weighted average remaining contractual term of options exercisable			5 years 4 months 10 days
Aggregate Intrinsic Value
Aggregate intrinsic value of options outstanding (in dollars)			517,164		501,706
Aggregate intrinsic value of options, vested and non-vested options expected to vest (in dollars)			478,893
Aggregate intrinsic value of options exercisable (in dollars)			257,418
Status of the Company's non-vested options and changes during the year
Non-vested options at the beginning of the period (in shares)			8,016,921
Non-vested options, options granted (in shares)			32,500
Non-vested options, options vested (in shares)			(7,000)
Non-vested options, options forfeited (in shares)			(51,460)
Non-vested options at the end of the period (in shares)			7,990,961		8,016,921
Weighted Average Fair Value at Grant Date
Weighted average fair value at the grant date, options outstanding at the beginning of the period (in dollars per share)			$ 14.77
Weighted average fair value at grant date, options granted (in dollars per share)			$ 21.23
Weighted average fair value at grant date, options vested (in dollars per share)			$ 16.98
Weighted average fair value at grant date, options forfeited (in dollars per share)			$ 14.82
Weighted average fair value at the grant date, options outstanding at the end of the period (in dollars per share)			$ 14.79		$ 14.77
Total intrinsic value of stock options exercised (in dollars)			15,560	40,542
Total fair value of stock options vested (in dollars)			119	135
Total compensation cost related to non-vested options not yet recognized (in dollars)			76,647
Weighted average expected amortization period			3 years 2 months 19 days			1 month 24 days
Number of restricted shares issued							12,824	17,045
Weighted-average grant date fair value of restricted shares (in dollars per share)							$ 78.00	$ 53.78
Total compensation cost related to non-vested restricted shares not yet recognized (in dollars)						$ 155