Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at at Dec. 31, 2019	$ 460,342	$ 593	$ 475,720	$ 45,895	$ (61,866)
Balance at (in shares) at Dec. 31, 2019		59,329,431
Stock-based compensation plans
Stock Issued During Period, Value, Restricted Stock Award, Gross	0	$ 2	(2)
Grant of restricted stock (in shares)		201,400
Stock Issued During Period, Value, Share-based Compensation, Withholdings of Common Shares, Net of Issuances	(1,839)	$ 1	(1,840)
Withholdings of common shares, net of issuances (in shares)		59,439
Stock Issued During Period, Value, Restricted Stock Award, Forfeitures	0	$ 0	0
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	3,951		3,951
Forfeited restricted stock (in shares)		(500)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	34,079			32,579
Balance at at Jun. 30, 2020	496,533	$ 596	477,829	78,474	(60,366)
Balance at (in shares) at Jun. 30, 2020		59,589,770
Stock-based compensation plans
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	1,500
Balance at at Mar. 31, 2020	599,303	$ 596	476,423	183,400	(61,116)
Balance at (in shares) at Mar. 31, 2020		59,623,195
Stock-based compensation plans
Stock Issued During Period, Value, Restricted Stock Award, Gross	0	$ 0	0
Grant of restricted stock (in shares)		900
Withholdings of common shares, net of issuances	(724)	$ 0	(724)
Issuance of common shares, net of withholdings (in shares)		(33,825)
Stock Issued During Period, Value, Restricted Stock Award, Forfeitures	0	$ 0	0
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	2,130		2,130
Forfeited restricted stock (in shares)		(500)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(104,176)			(104,926)
Balance at at Jun. 30, 2020	496,533	$ 596	477,829	78,474	(60,366)
Balance at (in shares) at Jun. 30, 2020		59,589,770
Stock-based compensation plans
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	750
Balance at at Dec. 31, 2020	$ 855,497	$ 596	855,547	78,010	(78,656)
Balance at (in shares) at Dec. 31, 2020	59,560,036	59,560,036
Stock-based compensation plans
Stock Issued During Period, Value, Restricted Stock Award, Gross	$ 0	$ 1	(1)
Grant of restricted stock (in shares)		122,100
Withholdings of common shares, net of issuances	(1,236)	$ 1	(1,237)
Issuance of common shares, net of withholdings (in shares)		92,234
Conversion of Stock, Amount Converted	131,967	$ 144	131,823
Conversion of Stock, Shares Converted		14,428,445
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	3,479		3,479
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	125,020				122,224
Balance at at Jun. 30, 2021	$ 1,114,727	$ 742	989,611	200,234	(75,860)
Balance at (in shares) at Jun. 30, 2021	74,202,815	74,202,815
Stock-based compensation plans
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent					2,796
Balance at at Mar. 31, 2021	$ 899,738	$ 606	856,090	120,300	(77,258)
Balance at (in shares) at Mar. 31, 2021		60,641,436
Stock-based compensation plans
Stock Issued During Period, Value, Restricted Stock Award, Gross	0	$ 0	0
Grant of restricted stock (in shares)		0
Withholdings of common shares, net of issuances	(39)	$ 0	(39)
Issuance of common shares, net of withholdings (in shares)		(1,518)
Conversion of Stock, Amount Converted	131,967	$ 136	131,831
Conversion of Stock, Shares Converted		13,562,897
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	1,729		1,729
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	81,332			79,934
Balance at at Jun. 30, 2021	$ 1,114,727	$ 742	$ 989,611	$ 200,234	$ (75,860)
Balance at (in shares) at Jun. 30, 2021	74,202,815	74,202,815
Stock-based compensation plans
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	$ 1,398