Earnings per Share Purchase of Common Stock (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Repurchased and Retired During Period, Value	$ 12,140
10b5-1 share repurchase program [Member]
Stock Repurchase Program, Authorized Amount	$ 50,000
Stock Repurchased and Retired During Period, Shares	442,632	0	0
Stock Repurchased and Retired During Period, Value	$ 12,100	$ 0	$ 0

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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