Equity Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Stock options	Jun. 30, 2012 Stock options	Jun. 30, 2013 Stock options	Jun. 30, 2012 Stock options	Jun. 30, 2013 Stock options Maximum	Jun. 30, 2013 RSUs Market price of $64.00 per share Non-employee directors	Jun. 30, 2013 RSUs Market price of $80.00 per share Non-employee directors	Jun. 30, 2013 RSUs Market price of $50.31 per share Non-employee directors	Jun. 30, 2013 RSUs Market price of $73.00 per share Non-employee directors	Oct. 31, 2012 Holding Stock options Key management employees
Equity based compensation
Strike price (in dollars per share)														$ 34.31
Strike price before revision (in dollars per share)														$ 64.00
Term of awards									10 years
Compensation charge	$ 1,062	$ 1,062	$ 2,124	$ 2,124	$ 1,100	$ 1,100	$ 2,100	$ 2,100
Number of shares granted										3,945	789	2,694	991
Market price (in dollars per share)										$ 64.00	$ 80.00	$ 50.31	$ 73.00