Fair Value of Financial Instruments (Details 3)	1 Months Ended			12 Months Ended
	Dec. 31, 2012 Interest rate swaps USD ($)	Mar. 31, 2011 Interest rate swaps USD ($) contract	Dec. 31, 2013 Interest rate swaps Scenario, forecast USD ($)	Sep. 30, 2014 Cross currency swaps USD ($)	Sep. 30, 2014 Cross currency swaps GBP (£)	Sep. 30, 2013 Cross currency swaps USD ($)	Sep. 30, 2012 Cross currency swaps USD ($)	Dec. 31, 2010 Cross currency swaps contract
Derivative information
Number of derivative contracts entered into by the entity		3						3
Notional amount of each derivative contract	$ 266,666,000	$ 333,333,000	$ 166,666,000	$ 300,000,000	£ 194,200,000
Notional amount of derivative contracts		1,000,000,000
Fixed interest rate (as a percent)		1.92%
Forward rate (as a percent)				1.56	1.56
Hedge ineffectiveness (gain) / loss				$ 966,000		$ 1,611,000	$ (3,358,000)