Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Nov. 27, 2019	May 08, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Nov. 06, 2018	May 10, 2017
Class of Stock [Line Items]
Common stock shares authorized			100,000,000		100,000,000		100,000,000
Common stock, par value			$ 0.01		$ 0.01		$ 0.01
Preferred stock shares authorized			50,000,000		50,000,000		50,000,000
Preferred stock, par value			$ 0.01		$ 0.01		$ 0.01
Common stock shares issued			33,350,633		33,350,633		33,067,375
Common stock shares outstanding			33,350,633		33,350,633		33,067,375
Gross proceeds from issuances of common stock						$ 25,817
Number of shares authorized to be repurchased								4,500,000
Common stock shares repurchased, shares				83,000		83,000
Common stock shares repurchased, value				$ 1,400		$ 1,439
First Amended And Restated 2013 Long-Term Incentive Plan [Member]
Class of Stock [Line Items]
Common stock shares for stock award issuance									1,800,000
2017 Incentive Plan [Member]
Class of Stock [Line Items]
Common stock shares rolled into plan									600,000
Amended 2017 Incentive Plan [Member]
Class of Stock [Line Items]
Additional shares authorized		1,631,000
Common stock shares for stock award, available for issuance			1,000,000.0		1,000,000.0
Common stock shares issued related to vesting of RSUs					500,000	300,000
Distribution Agreement [Member]
Class of Stock [Line Items]
Aggregate offering price	$ 100,000
Available for sale			$ 100,000		$ 100,000
Common stock shares sold and issued			0	800,000	0	900,000
Gross proceeds from issuances of common stock				$ 23,700		$ 26,500
Comissions and fees paid to sales agents				$ 600		$ 700