Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands		Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income
Balance, beginning of year (in shares) at Dec. 31, 2018			25,097,408
Balance, beginning of year at Dec. 31, 2018		$ 888,375	$ 25	$ 203,350	$ 715,472	$ (30,472)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		44,521			44,521
Stock based compensation		3,438		3,438
Stock based compensation (in shares)			70,414
Dividends on common stock		(7,797)			(7,797)
Change in net unrealized investment appreciation	[1]	26,279				26,279
Change in liability for underfunded employee benefit plans	[2]	888				888
Balance, end of year (in shares) at Mar. 31, 2019			25,167,822
Balance, end of year at Mar. 31, 2019		$ 955,191	$ 25	206,788	751,683	(3,305)
Balance, beginning of year (in shares) at Dec. 31, 2019		25,015,963	25,015,963
Balance, beginning of year at Dec. 31, 2019		$ 910,472	$ 25	200,179	697,116	13,152
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(72,534)			(72,534)
Shares repurchased (in shares)			(70,467)
Shares repurchased		(2,741)		(2,741)
Stock based compensation (in shares)			70,597
Stock based compensation		879		879
Dividends on common stock		(8,249)			(8,249)
Change in net unrealized investment appreciation	[1]	4,500				4,500
Change in liability for underfunded employee benefit plans	[2]	$ 847				847
Balance, end of year (in shares) at Mar. 31, 2020		25,016,093	25,016,093
Balance, end of year at Mar. 31, 2020		$ 833,144	$ 25	$ 198,317	$ 616,303	$ 18,499

[1] The change in net unrealized appreciation is net of reclassification adjustments and income taxes.

[2] The change in liability for underfunded employee benefit plans is net of reclassification adjustments and income taxes.