Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended	12 Months Ended
	Jul. 03, 2018	Aug. 09, 2017	Nov. 07, 2016	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2018
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				30,154,791	30,154,791	29,502,624
Common stock shares outstanding				30,154,791	30,154,791	29,502,624
Common stock shares issued related to vesting of RSUs					300,000
Net proceeds from issuances of common stock					$ 30,947	$ 98,063	$ 11,369
Number of shares authorized to be repurchased								4,500,000
Common stock shares repurchased, shares				604,061
Common stock shares repurchased, value				$ 11,000	$ 10,952		$ 2,393
Common Stock [Member]
Class of Stock [Line Items]
Common stock shares repurchased, shares					604,000		159,000
Common stock shares repurchased, value					$ 6		$ 2
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	1,800,000
2017 Incentive Plan [Member]
Class of Stock [Line Items]
Common stock shares for stock award, available for issuance				900,000	900,000	1,200,000
Common stock shares rolled into plan				600,000	600,000
First Distribution Agreement [Member]
Class of Stock [Line Items]
Aggregate offering price			$ 50,000
Second Distribution Agreement [Member]
Class of Stock [Line Items]
Aggregate offering price		$ 100,000
Third Distribution Agreement [Member]
Class of Stock [Line Items]
Aggregate offering price	$ 100,000
Second And Third Distribution Agreements [Member]
Class of Stock [Line Items]
Common stock shares sold and issued					1,100,000	3,700,000
Net proceeds from issuances of common stock					$ 31,700	$ 98,100
Comissions and fees paid to Sales Agents					$ 700	$ 2,000