Common Stock Repurchase Program	6 Months Ended
Jun. 30, 2016
Notes To Financial Statements [Abstract]
Common Stock Repurchase	Common Stock Repurchase In April 2014, we announced that our Board of Directors had authorized a stock repurchase program ("April 2014 Repurchase Program") pursuant to which we may purchase up to $300.0 million of our common stock over the next three years. As of June 30, 2016, we have approximately $50.0 million remaining under the April 2014 Repurchase Program. On May 3, 2016, as part of our $300.0 million April 2014 Repurchase Program, we entered into an ASR to repurchase $50.0 million of our common stock (the "2016 ASR"). Under the terms of the 2016 ASR, we paid $50.0 million and received an initial delivery of approximately 0.5 million shares based on the then current market price of $74.90, which we retired. The final delivery of shares is scheduled during October 2016, with the number of shares to be determined by the Company's volume weighted-average stock price during the term of the ASR less an agreed upon discount. After the completion of the 2016 ASR, we will commence repurchasing $50.0 million of our common stock on the open market. These two actions will complete the April 2014 Repurchase Program. On April 28, 2016, we announced that our Board of Directors had authorized a plan to repurchase up to $300.0 million of the Company's stock. This latest authorization is in addition to the existing $300 million authorization announced in April 2014, which brings the total authorization to $600 million. Any purchases under this stock repurchase program may be made, from time-to-time, pursuant to open market purchases (including pursuant to Rule 10b5-1 plans), privately-negotiated transactions, accelerated stock repurchases, block trades or derivative contracts or otherwise in accordance with applicable federal securities laws, including Rule 10b-18 of the Securities Exchange Act of 1934.

Common Stock Repurchase

In April 2014, we announced that our Board of Directors had authorized a stock repurchase program ("April 2014 Repurchase Program") pursuant to which we may purchase up to $300.0 million of our common stock over the next three years. As of June 30, 2016, we have approximately $50.0 million remaining under the April 2014 Repurchase Program. On May 3, 2016, as part of our $300.0 million April 2014 Repurchase Program, we entered into an ASR to repurchase $50.0 million of our common stock (the "2016 ASR"). Under the terms of the 2016 ASR, we paid $50.0 million and received an initial delivery of approximately 0.5 million shares based on the then current market price of $74.90, which we retired. The final delivery of shares is scheduled during October 2016, with the number of shares to be determined by the Company's volume weighted-average stock price during the term of the ASR less an agreed upon discount. After the completion of the 2016 ASR, we will commence repurchasing $50.0 million of our common stock on the open market. These two actions will complete the April 2014 Repurchase Program.

On April 28, 2016, we announced that our Board of Directors had authorized a plan to repurchase up to $300.0 million of the Company's stock. This latest authorization is in addition to the existing $300 million authorization announced in April 2014, which brings the total authorization to $600 million. Any purchases under this stock repurchase program may be made, from time-to-time, pursuant to open market purchases (including pursuant to Rule 10b5-1 plans), privately-negotiated transactions, accelerated stock repurchases, block trades or derivative contracts or otherwise in accordance with applicable federal securities laws, including Rule 10b-18 of the Securities Exchange Act of 1934.