Cash Dividends	12 Months Ended
Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Cash Dividends	Cash Dividends On January 27, 2015, our board of directors declared that the regular quarterly dividends to be paid to our stockholders in 2015 will be $0.15 per share of common stock, payable on March 12, June 12, September 11 and December 11 of 2015 to stockholders of record on March 5, June 5, September 4 and December 4 of 2015, the record dates for each of the dividend payments, respectively. On January 29, 2014, our board of directors declared a regular quarterly dividend of $0.15 per share of common stock, which were paid on March 12, June 12, September 12 and December 12 of 2014 to stockholders of record on March 5, June 5, September 5 and December 5 of 2014, the record dates for each of the dividend payments, respectively. We paid $96.6 million in dividends in 2014. On January 23, 2013, our board of directors declared a regular quarterly dividend of $0.15 per share of common stock, which were paid on March 12, June 12, September 12 and December 12 of 2013 to stockholders of record on March 5, June 5, September 5 and December 5 of 2013, the record dates for each of the dividend payments, respectively. We paid $84.0 million in dividends in 2013. On January 18, 2012, our board of directors declared regular quarterly dividends of $0.15 per share of common stock, which were paid on March 14, June 14, September 14 and December 14 of 2012 to stockholders of record on March 7, June 7, September 7 and December 7 of 2012, the record dates for each of the dividend payments, respectively. We paid $83.9 million in dividends in 2012.

Cash Dividends

12 Months Ended

Dec. 31, 2014

Stockholders' Equity Note [Abstract]

On January 27, 2015, our board of directors declared that the regular quarterly dividends to be paid to our stockholders in 2015 will be $0.15 per share of common stock, payable on March 12, June 12, September 11 and December 11 of 2015 to stockholders of record on March 5, June 5, September 4 and December 4 of 2015, the record dates for each of the dividend payments, respectively.

On January 29, 2014, our board of directors declared a regular quarterly dividend of $0.15 per share of common stock, which were paid on March 12, June 12, September 12 and December 12 of 2014 to stockholders of record on March 5, June 5, September 5 and December 5 of 2014, the record dates for each of the dividend payments, respectively. We paid $96.6 million in dividends in 2014.

On January 23, 2013, our board of directors declared a regular quarterly dividend of $0.15 per share of common stock, which were paid on March 12, June 12, September 12 and December 12 of 2013 to stockholders of record on March 5, June 5, September 5 and December 5 of 2013, the record dates for each of the dividend payments, respectively. We paid $84.0 million in dividends in 2013.

On January 18, 2012, our board of directors declared regular quarterly dividends of $0.15 per share of common stock, which were paid on March 14, June 14, September 14 and December 14 of 2012 to stockholders of record on March 7, June 7, September 7 and December 7 of 2012, the record dates for each of the dividend payments, respectively. We paid $83.9 million in dividends in 2012.