Capital Stock (Details) (USD $)	1 Months Ended	6 Months Ended
	May 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Capital Stock
Common stock, shares authorized		200,000,000	200,000,000
Preferred stock, shares authorized		15,000,000	15,000,000
Preferred stock outstanding (in shares)		0
Summary of issued and outstanding common stock activity
Beginning balance, shares		87,152,197
Issuance of restricted stock awards, shares		14,000
Common stock reacquired and retired, shares		(117,000)
Restricted stock forfeited and retired, shares		(101,000)
Option exercises, net of cancellations		74,000
Ending balance, shares		87,021,935
Dividends
Cash dividend declared (in dollars per share)	$ 0.16