Share Repurchases (Notes)	12 Months Ended
Dec. 31, 2015
Share Repurchase Program [Abstract]
Share Repurchase Program [Text Block]	Share Repurchase Program The Company's Board of Directors authorized a share repurchase program (the “Share Repurchase Program”), effective as of January 1, 2004. The Share Repurchase Program does not have a fixed expiration or termination date and may be modified or terminated by the Board of Directors at any time. On several occasions the Board of Directors has increased the amount authorized for repurchase. The Share Repurchase Program permits the Company to effect repurchases from time to time through a combination of open market repurchases or in privately negotiated transactions at such prices and times as are determined to be in the best interest of the Company. During the twelve months ended December 31, 2015, an aggregate of 3,704,109 shares of the Company's common stock was repurchased under the Share Repurchase Program, at an average price per share of $36.62, for an aggregate purchase price of approximately $135,637. As of December 31, 2015, approximately $64,127 remained available for future repurchases under the Share Repurchase Program. Subsequent to the year ended December 31, 2015, on February 22, 2016, the Board of Directors approved the extension of the Share Repurchase Program for an additional $136,000 in repurchases of the Company's common stock resulting in approximately $200,000 currently available for future repurchases.

Share Repurchase Program

The Company's Board of Directors authorized a share repurchase program (the “Share Repurchase Program”), effective as of January 1, 2004. The Share Repurchase Program does not have a fixed expiration or termination date and may be modified or terminated by the Board of Directors at any time. On several occasions the Board of Directors has increased the amount authorized for repurchase. The Share Repurchase Program permits the Company to effect repurchases from time to time through a combination of open market repurchases or in privately negotiated transactions at such prices and times as are determined to be in the best interest of the Company. During the twelve months ended December 31, 2015, an aggregate of 3,704,109 shares of the Company's common stock was repurchased under the Share Repurchase Program, at an average price per share of $36.62, for an aggregate purchase price of approximately $135,637. As of December 31, 2015, approximately $64,127 remained available for future repurchases under the Share Repurchase Program. Subsequent to the year ended December 31, 2015, on February 22, 2016, the Board of Directors approved the extension of the Share Repurchase Program for an additional $136,000 in repurchases of the Company's common stock resulting in approximately $200,000 currently available for future repurchases.