Common Stock - Schedule of Summary of Changes in Common Stock (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Increase (Decrease) in Common Stock [Roll Forward]
Beginning Balance	28,736
Ending Balance	28,880	28,736
Common Stock [Member]
Increase (Decrease) in Common Stock [Roll Forward]
Beginning Balance	28,736	28,630	27,427
Sales to employees under ESPP	19	18	18
Stock-based compensation	64	88	173
Equity Issuance			1,012
Stock Issued During Period, Shares, Dividend Reinvestment Plan	61
Ending Balance	28,880	28,736	28,630