Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 17,803	$ 14,616	$ 31,182	$ 28,653
Basic EPS, Shares	82,330	83,294	82,817	83,293
Basic EPS, Per Share Amount	$ 0.22	$ 0.18	$ 0.38	$ 0.34
Effect of restricted stock	$ 0	$ 0	$ 0	$ 0
Effect of restricted stock, Shares	38	44	38	44
Diluted EPS, Net Income	$ 17,803	$ 14,616	$ 31,182	$ 28,653
Diluted EPS, Shares	82,368	83,338	82,855	83,337
Diluted EPS, Per Share Amount	$ 0.22	$ 0.18	$ 0.38	$ 0.34