401(k) Plans	12 Months Ended
Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
401(k) Plans	We have a defined contribution plan, which generally covers all non-union United States employees meeting certain service requirements. Eligible employees may elect to defer from 1% to 25% of compensation per pay period up to the amount allowed by the Internal Revenue Code of 1986, as amended. In addition, IME operates a defined contribution plan, which is similar to our United States 401(k) Plan. We make matching contributions based on the amount of an employee's contribution in accordance with the plan documents. We have expensed $19,999, $18,306 and $16,355 for the years ended December 31, 2013, 2014 and 2015, respectively.

401(k) Plans

12 Months Ended

Dec. 31, 2015

Compensation and Retirement Disclosure [Abstract]

We have a defined contribution plan, which generally covers all non-union United States employees meeting certain service requirements. Eligible employees may elect to defer from 1% to 25% of compensation per pay period up to the amount allowed by the Internal Revenue Code of 1986, as amended. In addition, IME operates a defined contribution plan, which is similar to our United States 401(k) Plan. We make matching contributions based on the amount of an employee's contribution in accordance with the plan documents. We have expensed $19,999, $18,306 and $16,355 for the years ended December 31, 2013, 2014 and 2015, respectively.