Capital Stock (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000
Preferred stock, par value	$ 0.01
Common Stock, Shares, Outstanding	78,855,547	78,112,032	77,423,415
Treasury stock, shares held	2,478,084	2,334,137	2,249,959
Preferred stock, shares issued	0
Common Shares Outstanding and Treasury Shares Held Rollforward [Table]
Common shares outstanding, beginning balance	78,112,032	77,423,415	76,291,745
Exercise of common stock options, net	373,106	580,097	858,727
Grants of restricted stock, net	370,409	108,520	272,943
Common shares outstanding, ending balance	78,855,547	78,112,032	77,423,415
Treasury stock, beginning balance	2,334,137	2,249,959	1,533,653
Shares received upon exercise of common stock options	119,477	81,616	592,992
Shares received upon vesting of restricted stock, net	24,470	2,562	123,314
Treasury stock, ending balance	2,478,084	2,334,137	2,249,959
Amount authorized under stock repurchase program	$ 20,000,000
Amount repurchased under the stock repurchase program in the period	$ 0