Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Comprehensive Loss	Adoption of ASC 842	Adoption of ASC 842 Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2018		53,630,204
Beginning balance at Dec. 31, 2018	$ 471,392	$ 536	$ 1,184,132	$ (700,623)	$ (12,653)	$ 96	$ 96
Increase (Decrease) in Stockholders' Equity
Dividends on common stock	(8,158)			(8,158)
Share-based compensation	1,119		1,119
Change in fair value of cash flow hedging derivatives in other comprehensive loss	(6,622)				(6,622)
Net loss	(18,508)			(18,508)
Ending balance (in shares) at Mar. 31, 2019		53,630,204
Ending balance at Mar. 31, 2019	439,319	$ 536	1,185,251	(727,193)	(19,275)
Beginning balance (in shares) at Dec. 31, 2018		53,630,204
Beginning balance at Dec. 31, 2018	471,392	$ 536	1,184,132	(700,623)	(12,653)	$ 96	$ 96
Increase (Decrease) in Stockholders' Equity
Change in fair value of cash flow hedging derivatives in other comprehensive loss	(8,889)
Net loss	(79,893)
Ending balance (in shares) at Sep. 30, 2019		53,880,544
Ending balance at Sep. 30, 2019	361,866	$ 539	1,187,973	(805,104)	(21,542)
Beginning balance (in shares) at Mar. 31, 2019		53,630,204
Beginning balance at Mar. 31, 2019	439,319	$ 536	1,185,251	(727,193)	(19,275)
Increase (Decrease) in Stockholders' Equity
Common shares issued under share-based compensation plans (in shares)		234,389
Common shares issued under share-based compensation plans	61	$ 2	59
Shares withheld for taxes upon vesting of restricted stock (in shares)		(38,135)
Shares withheld for taxes upon vesting of restricted stock	(438)	$ 0	(438)
Dividends on common stock	(8,258)			(8,258)
Share-based compensation	1,811		1,811
Change in fair value of cash flow hedging derivatives in other comprehensive loss	(2,234)				(2,234)
Net loss	(25,017)			(25,017)
Ending balance (in shares) at Jun. 30, 2019		53,826,458
Ending balance at Jun. 30, 2019	405,244	$ 538	1,186,683	(760,468)	(21,509)
Increase (Decrease) in Stockholders' Equity
Common shares issued under share-based compensation plans (in shares)		68,890
Common shares issued under share-based compensation plans	1	$ 1	0
Shares withheld for taxes upon vesting of restricted stock (in shares)		(14,804)
Shares withheld for taxes upon vesting of restricted stock	(167)	$ 0	(167)
Dividends on common stock	(8,268)			(8,268)
Share-based compensation	1,457		1,457
Change in fair value of cash flow hedging derivatives in other comprehensive loss	(33)				(33)
Net loss	(36,368)			(36,368)
Ending balance (in shares) at Sep. 30, 2019		53,880,544
Ending balance at Sep. 30, 2019	$ 361,866	$ 539	1,187,973	(805,104)	(21,542)
Beginning balance (in shares) at Dec. 31, 2019	53,933,575	53,933,575
Beginning balance at Dec. 31, 2019	$ 339,259	$ 539	1,189,236	(830,602)	(19,914)
Increase (Decrease) in Stockholders' Equity
Common shares issued under share-based compensation plans (in shares)		243,089
Common shares issued under share-based compensation plans	65	$ 3	62
Shares withheld for taxes upon vesting of restricted stock (in shares)		(64,290)
Shares withheld for taxes upon vesting of restricted stock	(768)	$ (1)	(767)
Dividends on common stock	(8,263)			(8,263)
Share-based compensation	1,487		1,487
Change in fair value of cash flow hedging derivatives in other comprehensive loss	(447)				(447)
Net loss	(20,215)			(20,215)
Ending balance (in shares) at Mar. 31, 2020		54,112,374
Ending balance at Mar. 31, 2020	$ 311,118	$ 541	1,190,018	(859,080)	(20,361)
Beginning balance (in shares) at Dec. 31, 2019	53,933,575	53,933,575
Beginning balance at Dec. 31, 2019	$ 339,259	$ 539	1,189,236	(830,602)	(19,914)
Increase (Decrease) in Stockholders' Equity
Change in fair value of cash flow hedging derivatives in other comprehensive loss	2,224
Net loss	$ (79,397)
Ending balance (in shares) at Sep. 30, 2020	58,747,146	58,747,146
Ending balance at Sep. 30, 2020	$ 311,744	$ 587	1,247,109	(918,262)	(17,690)
Beginning balance (in shares) at Mar. 31, 2020		54,112,374
Beginning balance at Mar. 31, 2020	311,118	$ 541	1,190,018	(859,080)	(20,361)
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, including shares under share-based compensation plans (in shares)		4,693,383
Issuance of common stock, including shares under share-based compensation plans	55,000	$ 47	54,953
Shares withheld for taxes upon vesting of restricted stock (in shares)		(58,611)
Shares withheld for taxes upon vesting of restricted stock	(415)	$ (1)	(414)
Share-based compensation	936		936
Change in fair value of cash flow hedging derivatives in other comprehensive loss	1,497				1,497
Net loss	3,995			3,995
Ending balance (in shares) at Jun. 30, 2020		58,747,146
Ending balance at Jun. 30, 2020	372,131	$ 587	1,245,493	(855,085)	(18,864)
Increase (Decrease) in Stockholders' Equity
Share-based compensation	1,616		1,616
Change in fair value of cash flow hedging derivatives in other comprehensive loss	1,174				1,174
Net loss	$ (63,177)			(63,177)
Ending balance (in shares) at Sep. 30, 2020	58,747,146	58,747,146
Ending balance at Sep. 30, 2020	$ 311,744	$ 587	$ 1,247,109	$ (918,262)	$ (17,690)