Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 19,056	$ 7,916	$ 50,237	$ 36,568
Basic EPS, Shares	81,965	83,303	82,530	83,296
Basic EPS, Per Share Amount	$ 0.23	$ 0.10	$ 0.61	$ 0.44
Effect of restricted stock	$ 0	$ 0	$ 0	$ 0
Effect of restricted stock, Shares	27	30	34	40
Diluted EPS, Net Income	$ 19,056	$ 7,916	$ 50,237	$ 36,568
Diluted EPS, Shares	81,992	83,333	82,564	83,336
Diluted EPS, Per Share Amount	$ 0.23	$ 0.09	$ 0.61	$ 0.44