Stock Compensation (Details 3) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2014	Mar. 31, 2016	Mar. 31, 2015
Stock Compensation Plans
Stock compensation expense		$ 20,800	$ 17,600
Other than options, disclosures
Assumed annualized forfeiture rate (as a percent)		5.00%
Stock compensation expense		$ 20,800	$ 17,600
Restricted Stock Units (RSUs)
Stock Compensation Plans
Number of shares awarded for each RSU (in shares)		1
Shares Available For Grant
Shares Available for Grant Beginning Balance (in shares)		834,433
Granted (in shares)		(216,711)
Cancelled (in shares)		12,843
Shares Available for Grant Ending Balance (in shares)		630,565
Shares Subject to Outstanding Options, Shares
Outstanding at the beginning of the period (in shares)		565,567
Granted (in shares)		216,711
Cancelled (in shares)		(12,843)
Outstanding at the end of the period (in shares)		769,435
Shares Subject to Outstanding Options, Weighted Average Exercise Price
Granted (in dollars per share)		$ 88.28
Cancelled (in dollars per share)		$ 67.62
Weighted-average fair value assumptions
Cliff vesting period		3 years
Other than options, disclosures
Granted (in shares)		216,711
Outstanding (in shares)		834,433
Restricted Stock Units (RSUs) | President And Chief Executive Officer
Shares Available For Grant
Cancelled (in shares)		133,333
Shares Available for Grant Ending Balance (in shares)		266,667
Shares Subject to Outstanding Options, Shares
Granted (in shares)	400,000
Percentage of units vesting at the end of each calendar year (as a percent)		16.70%
Other than options, disclosures
Granted (in shares)	400,000
Outstanding (in shares)		266,667
Performance Stock Units (PSUs)
Stock Compensation Plans
Stock compensation expense		$ 0
Other than options, disclosures
Stock compensation expense		$ 0
Performance Stock Units (PSUs) | Maximum
Other than options, disclosures
Multiplier conversion rate of units into common stock (as a percent)		125.00%