Stock-Based Compensation and Employee Benefit Plans (Details) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	12 Months Ended									1 Months Ended	12 Months Ended										12 Months Ended
	Oct. 31, 2012	Sep. 30, 2014 Holdings	Sep. 30, 2013 Holdings	Sep. 30, 2014 Senior management	Sep. 30, 2014 Other management	Sep. 30, 2014 Time-based awards	Sep. 30, 2013 Time-based awards	Sep. 30, 2012 Time-based awards	Sep. 30, 2014 Performance based awards	Sep. 30, 2013 Performance based awards	Nov. 30, 2010 Stock option	Sep. 30, 2014 Stock option	Sep. 30, 2013 Stock option	Sep. 30, 2014 Stock option Time-based awards	Sep. 30, 2013 Stock option Time-based awards	Sep. 30, 2012 Stock option Time-based awards	Sep. 30, 2014 Stock option Performance based awards	Sep. 30, 2013 Stock option Performance based awards	Sep. 30, 2012 Stock option Performance based awards	Nov. 30, 2010 Class A Common stock	Nov. 30, 2010 Class B Common stock	Sep. 30, 2014 Class B Common stock Stock option	Sep. 30, 2013 Class B Common stock Stock option	Sep. 30, 2012 Class B Common stock Stock option
Stock-Based Compensation and Employee Benefit Plans
Aggregate number of shares which may be issued																				50,268	208,404
Expiration period											10 years
Vesting period						5 years						5 years
Compensation deduction for tax purposes									$ 0	$ 0							$ 0	$ 0
Weighted-average grant date fair value (in dollars per share)						$ 167	$ 239	$ 108	$ 96
Dividend paid	$ 193,956	$ 445,537	$ 721,682
Weighted-average assumptions used for the options granted
Risk-free rate, minimum (as a percent)														0.02%	0.11%	0.10%	0.02%	0.11%	0.10%
Risk-free rate, maximum (as a percent)														3.65%	4.59%	3.12%	3.65%	4.59%	3.12%
Expected term														6 years 6 months	6 years 6 months	6 years 6 months	3 years 1 month 6 days	4 years 6 months	5 years 7 months 6 days
Expected volatility (as a percent)														37.00%	36.00%	37.00%	33.00%	37.00%	38.00%
Expected dividends (as a percent)														0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
Number of shares
Outstanding at beginning of period (in shares)												173,183	162,951
Granted (in shares)												13,430	19,180									13,430	19,180	24,850
Exercised (in shares)												(614)	(730)
Forfeited (in shares)												(46,352)	(8,218)
Outstanding at end of period (in shares)												139,647	173,183
Exercisable at end of period (in shares)												50,360	29,833
Number of shares available for future grant (in shares)												117,269
Weighted average exercise price
Outstanding at beginning of period (in dollars per share)												$ 179	$ 151
Granted (in dollars per share)												$ 473	$ 397
Exercised (in dollars per share)												$ 133	$ 124
Forfeited (in dollars per share)												$ 153	$ 124
Outstanding at end of period (in dollars per share)												$ 212	$ 179
Exercisable at end of period (in dollars per share)												$ 152	$ 139
Additional disclosures
Reduction in percentage of share-based compensation expense for estimated forfeitures				0.00%	5.00%