Earnings Per Share Components of Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Weighted Average Number of Shares Outstanding, Basic	89,357	89,215	89,333	89,188
Dilutive effect of potential common shares	204	0	204	0
Weighted Average Number of Shares Outstanding, Diluted	89,561	89,215	89,537	89,188