Condensed Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Impact of adoption	Preferred Stock	Common Stock	Additional Paid-In Capital	Treasury Stock	Retained Earnings / (Accumulated Deficit)	Retained Earnings / (Accumulated Deficit) Impact of adoption
Balance (in shares) at Dec. 31, 2018			0	48,103,000
Balance at Dec. 31, 2018	$ 277,589	$ 37	$ 0	$ 481	$ 341,139		$ (64,031)	$ 37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with equity-based plans (in shares)				147,000
Common stock issued in connection with equity-based plans	1,591			$ 1	1,590
Vesting of common stock subject to repurchase	2				2
Stock-based compensation expense	4,267				4,267
Net income attributable to common stockholders	9,010						9,010
Balance (in shares) at Mar. 31, 2019			0	48,250,000
Balance at Mar. 31, 2019	$ 292,496		$ 0	$ 482	346,998		(54,984)
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Balance (in shares) at Dec. 31, 2018			0	48,103,000
Balance at Dec. 31, 2018	$ 277,589	37	$ 0	$ 481	341,139		(64,031)	37
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchases of treasury stock (in shares)	0
Net income attributable to common stockholders	$ 22,806
Balance (in shares) at Jun. 30, 2019			0	48,482,000
Balance at Jun. 30, 2019	312,428		$ 0	$ 485	353,131		(41,188)
Balance (in shares) at Mar. 31, 2019			0	48,250,000
Balance at Mar. 31, 2019	292,496		$ 0	$ 482	346,998		(54,984)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with equity-based plans (in shares)				232,000
Common stock issued in connection with equity-based plans	701			$ 3	698
Vesting of common stock subject to repurchase	$ 2				2
Purchases of treasury stock (in shares)	0
Stock-based compensation expense	$ 5,433				5,433
Net income attributable to common stockholders	13,796						13,796
Balance (in shares) at Jun. 30, 2019			0	48,482,000
Balance at Jun. 30, 2019	$ 312,428		$ 0	$ 485	353,131		(41,188)
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning balance at Dec. 31, 2019	$ 11,210
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income / (loss) attributable to common stockholders	(236)
Ending balance at Mar. 31, 2020	10,974
Balance (in shares) at Dec. 31, 2019			0	48,701,000		0
Balance at Dec. 31, 2019	355,651	(816)	$ 0	$ 487	365,627	$ 0	(10,463)	(816)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with equity-based plans (in shares)				107,000
Common stock issued in connection with equity-based plans	$ 1,365			$ 1	1,364
Purchases of treasury stock (in shares)	147,153					147,000
Purchases of treasury stock	$ (5,149)					$ (5,149)
Stock-based compensation expense	6,358				6,358
Net income attributable to common stockholders	8,807						8,807
Balance (in shares) at Mar. 31, 2020			0	48,808,000		(147,000)
Balance at Mar. 31, 2020	$ 366,216		$ 0	$ 488	373,349	$ (5,149)	(2,472)
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning balance at Dec. 31, 2019	$ 11,210
Ending balance at Jun. 30, 2020	10,716
Balance (in shares) at Dec. 31, 2019			0	48,701,000		0
Balance at Dec. 31, 2019	355,651	$ (816)	$ 0	$ 487	365,627	$ 0	(10,463)	$ (816)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to common stockholders	25,802
Balance (in shares) at Jun. 30, 2020			0	49,071,000		(147,000)
Balance at Jun. 30, 2020	393,253		$ 0	$ 491	383,388	$ (5,149)	14,523
Beginning balance at Mar. 31, 2020	10,974
Increase (Decrease) in Temporary Equity [Roll Forward]
Net income / (loss) attributable to common stockholders	(370)
Accretion adjustments of redeemable noncontrolling interest to redemption value	112
Ending balance at Jun. 30, 2020	10,716
Balance (in shares) at Mar. 31, 2020			0	48,808,000		(147,000)
Balance at Mar. 31, 2020	366,216		$ 0	$ 488	373,349	$ (5,149)	(2,472)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with equity-based plans (in shares)				263,000
Common stock issued in connection with equity-based plans	$ 3,059			$ 3	3,056
Purchases of treasury stock (in shares)	0
Stock-based compensation expense	$ 7,095				7,095
Accretion adjustments of redeemable noncontrolling interest to redemption value	(112)				(112)
Net income attributable to common stockholders	16,995						16,995
Balance (in shares) at Jun. 30, 2020			0	49,071,000		(147,000)
Balance at Jun. 30, 2020	$ 393,253		$ 0	$ 491	$ 383,388	$ (5,149)	$ 14,523