Earnings Per Share Components of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Weighted Average Number of Shares Outstanding, Basic	89,489	89,357	89,459	89,333
Dilutive effect of potential common shares	136	204	143	204
Weighted Average Number of Shares Outstanding, Diluted	89,625	89,561	89,602	89,537