Capital Stock	12 Months Ended
Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Capital Stock	CAPITAL STOCK CAPITAL STOCK At December 31, 2015, our authorized capital stock consists of 200,000,000 shares of common stock, par value $0.01 per share, and 10,000,000 shares of preferred stock, par value $0.01 per share. TREASURY STOCK On February 28, 2014, our Board of Directors authorized the repurchase by us of up to $300.0 million of our common stock, inclusive of prior authorizations, by various means from time to time through and including December 31, 2019. Pursuant to this authorization and previous authorizations, in 2015 we repurchased a total of 139,421 shares of our common stock at an average price per share of $54.71, for a total purchase price of $7.6 million, and we completed a “modified Dutch auction” tender offer pursuant to which we repurchased 2,766,354 shares of our common stock from our stockholders at a price of $58.50 per share, for a total purchase price of $161.8 million, exclusive of $0.7 million of fees and expenses; and in 2014 we repurchased a total of 508,667 shares of our common stock at an average price per share of $48.47, for a total purchase price of $24.7 million. In 2013, pursuant to previous authorizations, we repurchased a total of 354,154 shares of our common stock at an average price per share of $46.90, for a total purchase price of $16.6 million, and we completed a “modified Dutch auction” tender offer pursuant to which we repurchased 5,524,861 shares of our common stock from our stockholders at a price of $45.25 per share, for a total purchase price of $250.0 million, exclusive of $1.0 million of fees and expenses. Mr. Horrigan, our Non-Executive Co-Chairman of our Board of Directors, participated in the 2013 tender offer, and we purchased 515,806 shares beneficially owned by him at a price of $45.25 per share, for a total purchase price of $23.3 million, in the 2013 tender offer. At December 31, 2015, we had approximately $106.0 million remaining for the repurchase of our common stock under the February 28, 2014 authorization. In 2015, 2014 and 2013, we issued 146,160, 531,024 and 149,304 treasury shares, respectively, at an average cost of $6.30, $6.30 and $6.63 per share, respectively, for restricted stock units that vested during these years. In 2015, 2014 and 2013, we repurchased 50,841, 234,440 and 58,812 shares of our common stock, respectively, at an average cost of $56.88, $48.87 and $43.55 per share, respectively, in accordance with the Plan to satisfy employee withholding tax requirements resulting from certain restricted stock units becoming vested. We account for treasury shares using the FIFO cost method. As of December 31, 2015, 27,163,343 shares of our common stock were held in treasury.

Capital Stock

12 Months Ended

Dec. 31, 2015

Stockholders' Equity Note [Abstract]

CAPITAL STOCK

At December 31, 2015, our authorized capital stock consists of 200,000,000 shares of common stock, par value $0.01 per share, and 10,000,000 shares of preferred stock, par value $0.01 per share.

TREASURY STOCK

On February 28, 2014, our Board of Directors authorized the repurchase by us of up to $300.0 million of our common stock, inclusive of prior authorizations, by various means from time to time through and including December 31, 2019. Pursuant to this authorization and previous authorizations, in 2015 we repurchased a total of 139,421 shares of our common stock at an average price per share of $54.71, for a total purchase price of $7.6 million, and we completed a “modified Dutch auction” tender offer pursuant to which we repurchased 2,766,354 shares of our common stock from our stockholders at a price of $58.50 per share, for a total purchase price of $161.8 million, exclusive of $0.7 million of fees and expenses; and in 2014 we repurchased a total of 508,667 shares of our common stock at an average price per share of $48.47, for a total purchase price of $24.7 million. In 2013, pursuant to previous authorizations, we repurchased a total of 354,154 shares of our common stock at an average price per share of $46.90, for a total purchase price of $16.6 million, and we completed a “modified Dutch auction” tender offer pursuant to which we repurchased 5,524,861 shares of our common stock from our stockholders at a price of $45.25 per share, for a total purchase price of $250.0 million, exclusive of $1.0 million of fees and expenses. Mr. Horrigan, our Non-Executive Co-Chairman of our Board of Directors, participated in the 2013 tender offer, and we purchased 515,806 shares beneficially owned by him at a price of $45.25 per share, for a total purchase price of $23.3 million, in the 2013 tender offer. At December 31, 2015, we had approximately $106.0 million remaining for the repurchase of our common stock under the February 28, 2014 authorization.

In 2015, 2014 and 2013, we issued 146,160, 531,024 and 149,304 treasury shares, respectively, at an average cost of $6.30, $6.30 and $6.63 per share, respectively, for restricted stock units that vested during these years. In 2015, 2014 and 2013, we repurchased 50,841, 234,440 and 58,812 shares of our common stock, respectively, at an average cost of $56.88, $48.87 and $43.55 per share, respectively, in accordance with the Plan to satisfy employee withholding tax requirements resulting from certain restricted stock units becoming vested.

We account for treasury shares using the FIFO cost method. As of December 31, 2015, 27,163,343 shares of our common stock were held in treasury.