Capital Stock	12 Months Ended
Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Capital Stock	CAPITAL STOCK CAPITAL STOCK At December 31, 2014, 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, we repurchased a total of 508,667 shares of our common stock in 2014 at an average price per share of $48.47, for a total purchase price of $24.7 million; 354,154 shares of our common stock in 2013 at an average price per share of $46.90, for a total purchase price of $16.6 million; and 805,346 shares of our common stock in 2012 at an average price per share of $42.33, for a total purchase price of $34.1 million. In addition, we completed a “modified Dutch auction” tender offer on February 8, 2013 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 that 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 that tender offer. At December 31, 2014, we had approximately $275.5 million remaining for the repurchase of our common stock under the authorization from February 28, 2014. In 2014, 2013 and 2012, we issued 531,024, 149,304 and 132,846 treasury shares, respectively, at an average cost of $6.30, $6.63 and $6.63 per share, respectively, for restricted stock units that vested during these years. In 2014, 2013 and 2012, we repurchased 234,440, 58,812 and 43,874 shares of our common stock, respectively, at an average cost of $48.87, $43.55 and $42.64 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, 2014, 24,352,887 shares of our common stock were held in treasury. 2015 TENDER OFFER On February 9, 2015, we commenced a "modified Dutch auction" tender offer, or the Offer, to purchase up to 3,652,968 shares of our common stock at a price per share of not less than $54.75 and not greater than $58.50, for an aggregate purchase price of up to $200.0 million. The Offer will expire, unless extended by us, at 5:00 p.m. Eastern Time on March 10, 2015. We expect to fund the purchase of shares tendered in the Offer from available cash on hand and revolving loan borrowings under the Credit Agreement.

Capital Stock

12 Months Ended

Dec. 31, 2014

Stockholders' Equity Note [Abstract]

CAPITAL STOCK

At December 31, 2014, 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, we repurchased a total of 508,667 shares of our common stock in 2014 at an average price per share of $48.47, for a total purchase price of $24.7 million; 354,154 shares of our common stock in 2013 at an average price per share of $46.90, for a total purchase price of $16.6 million; and 805,346 shares of our common stock in 2012 at an average price per share of $42.33, for a total purchase price of $34.1 million. In addition, we completed a “modified Dutch auction” tender offer on February 8, 2013 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 that 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 that tender offer. At December 31, 2014, we had approximately $275.5 million remaining for the repurchase of our common stock under the authorization from February 28, 2014.

In 2014, 2013 and 2012, we issued 531,024, 149,304 and 132,846 treasury shares, respectively, at an average cost of $6.30, $6.63 and $6.63 per share, respectively, for restricted stock units that vested during these years. In 2014, 2013 and 2012, we repurchased 234,440, 58,812 and 43,874 shares of our common stock, respectively, at an average cost of $48.87, $43.55 and $42.64 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, 2014, 24,352,887 shares of our common stock were held in treasury.

2015 TENDER OFFER

On February 9, 2015, we commenced a "modified Dutch auction" tender offer, or the Offer, to purchase up to 3,652,968 shares of our common stock at a price per share of not less than $54.75 and not greater than $58.50, for an aggregate purchase price of up to $200.0 million. The Offer will expire, unless extended by us, at 5:00 p.m. Eastern Time on March 10, 2015. We expect to fund the purchase of shares tendered in the Offer from available cash on hand and revolving loan borrowings under the Credit Agreement.