Stock-Based Compensation Plans (Details 1) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Summary of the changes in outstanding stock options
Stock Options Outstanding at January 1, 2014 (in shares)	3,504
Stock options, Granted (in shares)	538
Stock options, Exercised (in shares)	(590)
Stock options, Forfeited (in shares)	(64)
Stock Options Outstanding at March 31, 2014 (in shares)	3,388	3,504
Options exercisable at March 31, 2014 (in shares)	1,929
Vested and expected to vest as of March 31, 2014 (in shares)	3,262
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price, Outstanding at January 1, 2014 (usd per share)	$ 26.80
Weighted Average Exercise Price / Share, Granted (usd per share)	$ 38.16
Weighted Average Exercise Price / Share, Exercised (usd per share)	$ 27.98
Weighted Average Exercise Price / Share, Forfeited (usd per share)	$ 26.05
Weighted Average Exercise Price, Outstanding at March 31, 2014 (usd per share)	$ 28.42	$ 26.80
Options exercisable, Weighted Average Exercise Price (usd per share)	$ 26.84
Vested and expected to vest as of March 31, 2014 (usd per share)	$ 28.18
Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Remaining Contractual Term [Roll Forward]
Weighted Average Remaining Contractual Term, Outstanding at January 1, 2014	6 years 10 months	6 years 4 months 24 days
Weighted Average Remaining Contractual Term, Options Granted	10 years
Weighted Average Remaining Contractual Term, Options Exercised	4 years 5 months
Weighted Average Remaining Contractual Term, Options Forfeited	5 years 11 months
Weighted Average Remaining Contractual Term, Outstanding at March 31, 2014	6 years 10 months	6 years 4 months 24 days
Weighed average remaining contractual term, Options exercisable	5 years 6 months
Vested and expected to vest as of March 31, 2014	6 years 8 months