Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Comprehensive Loss
Beginning balance (in shares) at Dec. 31, 2017		53,447,950
Beginning balance at Dec. 31, 2017	$ 644,602	$ 534	$ 1,181,327	$ (537,259)	$ 0
Increase (Decrease) in Stockholders' Equity
Common shares issued under share-based compensation plans, net of shares withheld for employee taxes (in shares)		44,187
Common shares issued under share-based compensation plans, net of shares withheld for employee taxes	107	$ 1	106
Dividends on common stock	(8,071)			(8,071)
Share-based compensation	(414)		(414)
Net loss	(27,350)			(27,350)
Ending balance (in shares) at Mar. 31, 2018		53,492,137
Ending balance at Mar. 31, 2018	608,874	$ 535	1,181,019	(572,680)	0
Beginning balance (in shares) at Dec. 31, 2017		53,447,950
Beginning balance at Dec. 31, 2017	644,602	$ 534	1,181,327	(537,259)	0
Increase (Decrease) in Stockholders' Equity
Change in fair value of cash flow hedging derivatives in other comprehensive loss	0
Net loss	(96,619)
Ending balance (in shares) at Sep. 30, 2018		53,630,204
Ending balance at Sep. 30, 2018	525,276	$ 536	1,182,988	(658,248)	0
Beginning balance (in shares) at Mar. 31, 2018		53,492,137
Beginning balance at Mar. 31, 2018	608,874	$ 535	1,181,019	(572,680)	0
Increase (Decrease) in Stockholders' Equity
Common shares issued under share-based compensation plans, net of shares withheld for employee taxes (in shares)		92,502
Common shares issued under share-based compensation plans, net of shares withheld for employee taxes	1	$ 1	0
Shares withheld for taxes upon vesting of restricted stock (in shares)		(22,836)
Shares withheld for taxes upon vesting of restricted stock	(240)		(240)
Dividends on common stock	(8,142)			(8,142)
Share-based compensation	1,094		1,094
Net loss	(21,336)			(21,336)
Ending balance (in shares) at Jun. 30, 2018		53,561,803
Ending balance at Jun. 30, 2018	580,251	$ 536	1,181,873	(602,158)	0
Increase (Decrease) in Stockholders' Equity
Common shares issued under share-based compensation plans, net of shares withheld for employee taxes (in shares)		75,530
Common shares issued under share-based compensation plans, net of shares withheld for employee taxes	0	$ 0	0
Shares withheld for taxes upon vesting of restricted stock (in shares)		(7,129)
Shares withheld for taxes upon vesting of restricted stock	(85)		(85)
Dividends on common stock	(8,157)			(8,157)
Share-based compensation	1,200		1,200
Net loss	(47,933)			(47,933)
Ending balance (in shares) at Sep. 30, 2018		53,630,204
Ending balance at Sep. 30, 2018	$ 525,276	$ 536	1,182,988	(658,248)	0
Beginning balance (in shares) at Dec. 31, 2018	53,630,204	53,630,204
Beginning balance at Dec. 31, 2018	$ 471,392	$ 536	1,184,132	(700,623)	(12,653)
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	53,630,204
Beginning balance at Dec. 31, 2018	$ 471,392	$ 536	1,184,132	(700,623)	(12,653)
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	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, net of shares withheld for employee taxes (in shares)		234,389
Common shares issued under share-based compensation plans, net of shares withheld for employee taxes	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)		(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, net of shares withheld for employee taxes (in shares)		68,890
Common shares issued under share-based compensation plans, net of shares withheld for employee taxes	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)		(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	53,880,544
Ending balance at Sep. 30, 2019	$ 361,866	$ 539	$ 1,187,973	$ (805,104)	$ (21,542)