Share Repurchase Programs	6 Months Ended
Jun. 30, 2017
Equity [Abstract]
Share Repurchase Programs	Share Repurchase Programs On August 6, 2014, the Board of Directors authorized the repurchase of up to $200,000 of the Company’s outstanding common stock pursuant to an accelerated share repurchase program, and the Company entered into a $200,000 accelerated share repurchase program (the “2014 ASR Program”) with J.P. Morgan Chase Bank (the “ASR Counterparty”). The Company paid $200,000 to the ASR Counterparty in August 2014 and received 5,567,154 shares of its common stock, which represented approximately 80 percent of the shares expected to be purchased pursuant to the 2014 ASR Program, based on the closing price on August 6, 2014. Under the terms of the 2014 ASR Program, the ASR Counterparty was permitted, in accordance with the applicable requirements of the federal securities laws, to separately trade in the Company’s shares in connection with the hedging activities related to the 2014 ASR Program and as part of other aspects of the ASR Counterparty’s business. On February 13, 2015, the Company completed the 2014 ASR Program. Based on the terms of the 2014 ASR Program, the total number of shares repurchased under the 2014 ASR Program was based on the volume-weighted average price of the Company’s common stock, less a discount, during the repurchase period, which resulted in the Company receiving an additional 784,694 shares of its common stock from the ASR Counterparty at maturity. As a result, under the 2014 ASR Program, the Company paid a total of $200,000 to the ASR Counterparty and received a total of 6,351,848 shares (5,567,154 shares initially received, plus 784,694 shares received at maturity) of its common stock, which represents a volume weighted average price, as adjusted pursuant to the terms of the 2014 ASR Program, of $31.49 over the duration of the 2014 ASR Program. On February 20, 2015, the Board of Directors authorized a new program to repurchase up to $200,000, excluding commissions, of the Company’s common stock through December 31, 2016 (the “2015 Repurchase Program”). The 2015 Repurchase Program did not obligate the Company to acquire any specific number of shares and could have been suspended or discontinued at any time without notice. Under the 2015 Repurchase Program, shares could have been repurchased in privately negotiated and/or open market transactions, including under plans complying with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended. During 2015, subsequent to the Board of Directors’ February 20, 2015 authorization, the Company repurchased 2,751,454 shares of the Company’s common stock under the 2015 Repurchase Program for $108,821, including applicable commissions, which represented an average price of $39.55 per share. As of December 31, 2015, approximately $91,261 remained of the $200,000 2015 Repurchase Program. For the period January 1, 2016 through February 19, 2016, the Company repurchased an additional 497,094 shares of the Company’s common stock under the 2015 Repurchase Program for $17,622, including applicable commissions, which represented an average price of $35.45 per share. All repurchases under the 2015 Repurchase Program were made using cash resources. On February 19, 2016, the Board of Directors increased the amount under and expanded the duration of the 2015 Repurchase Program (as amended, the “2016 Repurchase Program”). The 2016 Repurchase Program amended and superseded the 2015 Repurchase Program and allowed the Company to repurchase up to $200,000, excluding commissions, of the Company’s common stock from February 22, 2016 through December 31, 2017. The approximately $73,654 remaining under the 2015 Repurchase Program as of February 19, 2016 was included in the $200,000 maximum amount authorized by the 2016 Repurchase Program. No other changes were made. The 2016 Repurchase Program did not obligate the Company to acquire any specific number of shares and could have been suspended or discontinued at any time without notice. Under the 2016 Repurchase Program, shares could have been repurchased in privately negotiated and/or open market transactions, including under plans complying with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended. For the period February 22, 2016 through December 31, 2016, the Company repurchased 2,630,433 shares of the Company’s common stock under the 2016 Repurchase Program for $90,377, including applicable commissions, which represented an average price of $34.36 per share. As of December 31, 2016, approximately $109,702 remained of the $200,000 2016 Repurchase Program. For the period January 1, 2017 through February 16, 2017, the Company repurchased an additional 383,690 shares of the Company’s common stock under the 2016 Repurchase Program for $14,080, including applicable commissions, which represented an average price of $36.70 per share. All repurchases under the 2016 Repurchase Program were made using cash resources. On February 16, 2017, the Board of Directors increased the amount under and expanded the duration of the 2016 Repurchase Program (as amended, the "2017 Repurchase Program"). The 2017 Repurchase Program amended and superseded the 2016 Repurchase Program and allows the Company to repurchase up to $300,000, excluding commissions, of the Company’s common stock through December 31, 2019. The approximately $95,634 remaining authorization under the 2016 Repurchase Program as of February 16, 2017 is included in the $300,000 maximum amount authorized by the 2017 Repurchase Program. No other changes were made. The 2017 Repurchase Program does not obligate the Company to acquire any specific number of shares and can be suspended or discontinued at any time without notice. Under the 2017 Repurchase Program, shares can be repurchased in privately negotiated and/or open market transactions, including under plans complying with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended. For the period February 17, 2017 through June 30, 2017, the Company repurchased an additional 657,501 shares of the Company’s common stock under the 2017 Repurchase Program for $24,488, including applicable commissions, which represented an average price of $37.24 per share. All repurchases under the 2017 Repurchase Program have been made using cash resources. In the first half of 2017, the Company repurchased 1,041,191 shares of the Company’s common stock under the 2016 Repurchase Program and the 2017 Repurchase Program for $38,567, including applicable commissions, which represented an average price of $37.04 per share. Since the share repurchases began in August 2014 through June 30, 2017, the Company has repurchased 13,272,020 shares of the Company’s common stock at an average cost of $34.31 per share.

Share Repurchase Programs

On August 6, 2014, the Board of Directors authorized the repurchase of up to $200,000 of the Company’s outstanding common stock pursuant to an accelerated share repurchase program, and the Company entered into a $200,000 accelerated share repurchase program (the “2014 ASR Program”) with J.P. Morgan Chase Bank (the “ASR Counterparty”). The Company paid $200,000 to the ASR Counterparty in August 2014 and received 5,567,154 shares of its common stock, which represented approximately 80 percent of the shares expected to be purchased pursuant to the 2014 ASR Program, based on the closing price on August 6, 2014. Under the terms of the 2014 ASR Program, the ASR Counterparty was permitted, in accordance with the applicable requirements of the federal securities laws, to separately trade in the Company’s shares in connection with the hedging activities related to the 2014 ASR Program and as part of other aspects of the ASR Counterparty’s business.

On February 13, 2015, the Company completed the 2014 ASR Program. Based on the terms of the 2014 ASR Program, the total number of shares repurchased under the 2014 ASR Program was based on the volume-weighted average price of the Company’s common stock, less a discount, during the repurchase period, which resulted in the Company receiving an additional 784,694 shares of its common stock from the ASR Counterparty at maturity. As a result, under the 2014 ASR Program, the Company paid a total of $200,000 to the ASR Counterparty and received a total of 6,351,848 shares (5,567,154 shares initially received, plus 784,694 shares received at maturity) of its common stock, which represents a volume weighted average price, as adjusted pursuant to the terms of the 2014 ASR Program, of $31.49 over the duration of the 2014 ASR Program.

On February 20, 2015, the Board of Directors authorized a new program to repurchase up to $200,000, excluding commissions, of the Company’s common stock through December 31, 2016 (the “2015 Repurchase Program”). The 2015 Repurchase Program did not obligate the Company to acquire any specific number of shares and could have been suspended or discontinued at any time without notice. Under the 2015 Repurchase Program, shares could have been repurchased in privately negotiated and/or open market transactions, including under plans complying with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended.

During 2015, subsequent to the Board of Directors’ February 20, 2015 authorization, the Company repurchased 2,751,454 shares of the Company’s common stock under the 2015 Repurchase Program for $108,821, including applicable commissions, which represented an average price of $39.55 per share. As of December 31, 2015, approximately $91,261 remained of the $200,000 2015 Repurchase Program.

For the period January 1, 2016 through February 19, 2016, the Company repurchased an additional 497,094 shares of the Company’s common stock under the 2015 Repurchase Program for $17,622, including applicable commissions, which represented an average price of $35.45 per share. All repurchases under the 2015 Repurchase Program were made using cash resources.

On February 19, 2016, the Board of Directors increased the amount under and expanded the duration of the 2015 Repurchase Program (as amended, the “2016 Repurchase Program”). The 2016 Repurchase Program amended and superseded the 2015 Repurchase Program and allowed the Company to repurchase up to $200,000, excluding commissions, of the Company’s common stock from February 22, 2016 through December 31, 2017. The approximately $73,654 remaining under the 2015 Repurchase Program as of February 19, 2016 was included in the $200,000 maximum amount authorized by the 2016 Repurchase Program. No other changes were made. The 2016 Repurchase Program did not obligate the Company to acquire any specific number of shares and could have been suspended or discontinued at any time without notice. Under the 2016 Repurchase Program, shares could have been repurchased in privately negotiated and/or open market transactions, including under plans complying with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended.

For the period February 22, 2016 through December 31, 2016, the Company repurchased 2,630,433 shares of the Company’s common stock under the 2016 Repurchase Program for $90,377, including applicable commissions, which represented an average price of $34.36 per share. As of December 31, 2016, approximately $109,702 remained of the $200,000 2016 Repurchase Program.

For the period January 1, 2017 through February 16, 2017, the Company repurchased an additional 383,690 shares of the Company’s common stock under the 2016 Repurchase Program for $14,080, including applicable commissions, which represented an average price of $36.70 per share. All repurchases under the 2016 Repurchase Program were made using cash resources.

On February 16, 2017, the Board of Directors increased the amount under and expanded the duration of the 2016 Repurchase Program (as amended, the "2017 Repurchase Program"). The 2017 Repurchase Program amended and superseded the 2016 Repurchase Program and allows the Company to repurchase up to $300,000, excluding commissions, of the Company’s common stock through December 31, 2019. The approximately $95,634 remaining authorization under the 2016 Repurchase Program as of February 16, 2017 is included in the $300,000 maximum amount authorized by the 2017 Repurchase Program. No other changes were made. The 2017 Repurchase Program does not obligate the Company to acquire any specific number of shares and can be suspended or discontinued at any time without notice. Under the 2017 Repurchase Program, shares can be repurchased in privately negotiated and/or open market transactions, including under plans complying with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended.

For the period February 17, 2017 through June 30, 2017, the Company repurchased an additional 657,501 shares of the Company’s common stock under the 2017 Repurchase Program for $24,488, including applicable commissions, which represented an average price of $37.24 per share. All repurchases under the 2017 Repurchase Program have been made using cash resources.

In the first half of 2017, the Company repurchased 1,041,191 shares of the Company’s common stock under the 2016 Repurchase Program and the 2017 Repurchase Program for $38,567, including applicable commissions, which represented an average price of $37.04 per share.

Since the share repurchases began in August 2014 through June 30, 2017, the Company has repurchased 13,272,020 shares of the Company’s common stock at an average cost of $34.31 per share.