Summary of Significant Accounting Policies - Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies
Net income	$ 3,461	$ 14,331	$ 18,272	$ (1,390)	$ 12,931	$ 10,724	$ 10,556	$ 7,068	$ 34,674	$ 41,279	$ 55,090
Weighted average common shares outstanding (in shares)	30,603	28,874	28,867	28,853	28,723	28,730	28,761	28,621	29,301	28,709	28,709
Weighted average common stock equivalents (in shares)											1
Total weighted average common shares outstanding and common stock equivalents (in shares)	30,603	28,874	28,867	28,853	28,723	28,730	28,761	28,621	29,301	28,709	28,710
Basic earnings (loss) per common share (in dollars per share)	$ 0.11	$ 0.50	$ 0.63	$ (0.05)	$ 0.45	$ 0.37	$ 0.37	$ 0.25	$ 1.18	$ 1.44	$ 1.92
Diluted earnings (loss) per common share (in dollars per share)	$ 0.11	$ 0.50	$ 0.63	$ (0.05)	$ 0.45	$ 0.37	$ 0.37	$ 0.25	$ 1.18	$ 1.44	$ 1.92
Dividend Payout ratio									71.20%	58.30%	41.70%