XML 26 R73.htm IDEA: XBRL DOCUMENT v3.3.1.900
Income Taxes - Additional Information (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Sep. 30, 2015
Sep. 30, 2014
Sep. 30, 2013
Sep. 30, 2012
Income Taxes [Line Items]        
Deferred income tax expenses as a result of enacted changes in tax laws or rates   $ 4,179 $ 14,671  
Corporate tax rate of the company 0.00% 0.00% 0.00%  
Net increase (decrease) in valuation allowances $ (16,042) $ 1,005    
Tax credits, net capital and operating loss carryforwards 451,247 541,666    
Tax credits, net capital and operating loss carryforwards having expiration date $ 98,912 133,345    
Tax credits, net capital and operating loss carryforwards expiration date Through 2035 for $98,912 in net operating losses      
Gross unrecognized tax benefits $ 126,706 123,942 $ 130,371 $ 133,874
Accrued income taxes payable for interest and penalties relating to unrecognized tax benefits 22,219 20,855    
Accrued income taxes payable recognized in the statements of income 1,364 $ 1,729    
Expected decrease in unrecognized tax benefits within next 12 months $ 3,660      
September 30, 2014 [Member]        
Income Taxes [Line Items]        
Tax credits, net capital and operating loss carryforwards expiration date Through 2034 for $133,345 in net operating losses