Earnings per Share (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income	$ 24,476	$ 19,913	$ 6,345	$ 19,503	$ 22,837	$ 8,352	$ 50,734	$ 50,692
Weighted average basic shares outstanding (in shares)	32,470,000			32,115,000			32,357,000	31,922,000
Common stock options and restricted stock (in shares)	300,000			456,000			320,000	602,000
Weighted average shares outstanding, diluted (in shares)	32,770,000			32,571,000			32,677,000	32,524,000
Common shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from earnings per share calculation (in shares)	346,000			247,000			324,000	328,000