Fair Value of Financial Instruments (Details 3)	1 Months Ended	3 Months Ended		3 Months Ended
	Dec. 31, 2010 Interest rate swaps USD ($) contract	Dec. 31, 2012 Interest rate swaps USD ($)	Mar. 31, 2011 Interest rate swaps contract	Dec. 31, 2012 Interest rate swaps December 2012 USD ($)	Dec. 31, 2012 Interest rate swaps December 2013 USD ($)	Dec. 31, 2012 Cross currency swaps USD ($)	Dec. 31, 2012 Cross currency swaps GBP (£)	Dec. 31, 2011 Cross currency swaps USD ($)	Dec. 31, 2010 Cross currency swaps contract
Derivative information
Number of derivative contracts entered into by the entity	3		3						3
Payment on termination of derivative contract	$ 1,525,000
Notional amount of each derivative contract		333,333,000		266,666,000	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%
Derivative term		4 years
Forward rate						1.565	1.565
Hedge ineffectiveness resulted in an expense						$ 64,000		$ 0