Earnings per Share (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income	$ 19,913	$ 6,345	$ 22,837	$ 8,352	$ 26,258	$ 31,189
Weighted average basic shares outstanding (in shares)	32,321,000		31,862,000		32,300,000	31,824,000
Common stock options and restricted stock (in shares)	321,000		691,000		330,000	674,000
Weighted average shares outstanding, diluted (in shares)	32,642,000		32,553,000		32,630,000	32,498,000
Common shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share calculation (in shares)	366,000		377,000		312,000	368,000