Significant Accounting Policies - Schedule of Basic Weighted Average Shares Reconciles to Diluted Weighted Average Shares Outstanding (Details) - shares shares in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Basic weighted average common shares outstanding (in shares)	75,955	75,819	75,690	75,749	76,211	76,831	77,466	77,996	75,803	77,126	79,715
Dilutive effect of stock options, restricted stock, performance share units and DCUs (in shares)									955	846	1,013
Diluted weighted average common shares outstanding (in shares)	76,806	76,880	76,674	76,699	77,091	77,646	78,297	78,856	76,758	77,972	80,728