Shareholders' Equity Rollforward (Details) - USD ($) $ in Thousands		3 Months Ended						6 Months Ended
		Jun. 30, 2020	Mar. 31, 2020		Jun. 30, 2019	Mar. 31, 2019		Jun. 30, 2020	Jun. 30, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
As of beginning balance		$ 684,319	$ 520,745		$ 408,944	$ 447,355		$ 520,745	$ 447,355
Net income (loss)		(94,715)	163,094		51,625	(38,697)		68,379	12,928
All Other Changes		935	556		985	380	[1]
As of ending balance		590,539	684,319		461,554	408,944		590,539	461,554
Share-based compensation		1,000			1,000			1,807	2,055
Accounting Standards Update 2016-13 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
As of beginning balance	[2]	(76)
As of ending balance	[2]		(76)
Accounting Standards Update 2016-02
Increase (Decrease) in Stockholders' Equity [Roll Forward]
As of beginning balance	[3]	(94)
As of ending balance	[3]		(94)
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
As of beginning balance		(60)	(59)		81	82		(59)	82
All Other Changes		(1)	(1)		(1)	(1)
As of ending balance		(61)	(60)		80	81		(61)	80
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
As of beginning balance		483,005	319,987		210,701	249,492		319,987	249,492
Net income (loss)		(94,715)	163,094		51,625	(38,697)
All Other Changes			0			0
As of ending balance		388,290	483,005		262,326	210,701		388,290	262,326
Retained Earnings | Accounting Standards Update 2016-13 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
As of beginning balance	[2]	(76)
As of ending balance	[2]		(76)
Retained Earnings | Accounting Standards Update 2016-02
Increase (Decrease) in Stockholders' Equity [Roll Forward]
As of beginning balance	[3]	(94)
As of ending balance	[3]		(94)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
As of beginning balance		152	151		151	151		151	151
All Other Changes			1			0
As of ending balance		152	152		151	151		152	151
Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
As of beginning balance		201,222	200,666		198,011	197,630		200,666	197,630
All Other Changes		936	556	[4]	986	381	[1]
As of ending balance		$ 202,158	$ 201,222		$ 198,997	$ 198,011		$ 202,158	$ 198,997

[1] Includes equity-classified share-based compensation of $2.1 million during the six months ended June 30, 2019. During the six months ended June 30, 2019, 26,671 shares of common stock were issued in connection with the vesting of certain RSUs, net of shares withheld for income taxes.

[2] to the adoption of ASU 2016–13 as of January 1, 2020 (see Note 4).

[3] 1  

[4] Includes equity-classified share-based compensation of $1.8 million during the six months ended June 30, 2020. During the six months ended June 30, 2020, 36,174 and 3,895 shares of common stock were issued in connection with the vesting of certain time-vested restricted stock units (“RSUs”) and performance restricted stock units (“PRSUs”), net of shares withheld for income taxes.