CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock Class A Common	Common Stock Class B Common	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income
Beginning balance (in shares) at Dec. 31, 2017		77,588,018	80,957,495	(14,620,175)
Beginning balance at Dec. 31, 2017	$ 642,772	$ 0	$ 1	$ (199,817)	$ 534,159	$ 308,905	$ (476)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	3,723				3,723
Exercise of stock options (in shares)		211,002
Exercise of stock options	1,450				1,450
Conversion Class B to Class A common stock (in shares)		348,810	(348,810)
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)		452,657
Shares withheld for employee taxes upon conversion of restricted stock (in shares)		(33,980)
Shares withheld for employee taxes upon conversion of restricted stock	(459)				(459)
Other comprehensive income	379						379
Net income (loss)	(16,834)					(16,834)
Ending balance (in shares) at Mar. 31, 2018		78,566,507	80,608,685	(14,620,175)
Ending balance at Mar. 31, 2018	631,761	$ 0	$ 1	$ (199,817)	538,873	292,801	(97)
Beginning balance (in shares) at Dec. 31, 2017		77,588,018	80,957,495	(14,620,175)
Beginning balance at Dec. 31, 2017	642,772	$ 0	$ 1	$ (199,817)	534,159	308,905	(476)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(28,144)
Ending balance (in shares) at Sep. 30, 2018		86,447,709	80,608,685	(14,620,175)
Ending balance at Sep. 30, 2018	702,018	$ 0	$ 1	$ (199,817)	615,782	281,491	4,561
Beginning balance (in shares) at Mar. 31, 2018		78,566,507	80,608,685	(14,620,175)
Beginning balance at Mar. 31, 2018	631,761	$ 0	$ 1	$ (199,817)	538,873	292,801	(97)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	2,609				2,609
Issuance of common stock related to business combination (in shares)		7,598,731
Issuance of common stock related to business combination	70,000				70,000
Exercise of stock options (in shares)		21,059
Exercise of stock options	163				163
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)		466,474
Shares withheld for employee taxes upon conversion of restricted stock (in shares)		(60,521)
Shares withheld for employee taxes upon conversion of restricted stock	(610)				(610)
Other comprehensive income	466						466
Net income (loss)	(10,466)					(10,466)
Ending balance (in shares) at Jun. 30, 2018		86,592,250	80,608,685	(14,620,175)
Ending balance at Jun. 30, 2018	693,923	$ 0	$ 1	$ (199,817)	611,035	282,335	369
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	4,732				4,732
Exercise of stock options (in shares)		2,000
Exercise of stock options	15				15
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)		(139,879)
Shares withheld for employee taxes upon conversion of restricted stock (in shares)		(6,662)
Shares withheld for employee taxes upon conversion of restricted stock	0				0
Other comprehensive income	4,192						4,192
Net income (loss)	(844)					(844)
Ending balance (in shares) at Sep. 30, 2018		86,447,709	80,608,685	(14,620,175)
Ending balance at Sep. 30, 2018	702,018	$ 0	$ 1	$ (199,817)	615,782	281,491	4,561
Beginning balance (in shares) at Dec. 31, 2018		86,679,575	80,608,685	(14,620,175)
Beginning balance at Dec. 31, 2018	682,589	$ 0	$ 1	$ (199,817)	618,674	270,471	(6,740)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	5,163				5,163
Conversion Class B to Class A common stock (in shares)		460,000	(460,000)
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)		759,409
Shares withheld for employee taxes upon conversion of restricted stock (in shares)		(82,978)
Shares withheld for employee taxes upon conversion of restricted stock	(1,086)				(1,086)
Other comprehensive income	(8,054)						(8,054)
Net income (loss)	(8,323)					(8,323)
Ending balance (in shares) at Mar. 31, 2019		87,816,006	80,148,685	(14,620,175)
Ending balance at Mar. 31, 2019	670,289	$ 0	$ 1	$ (199,817)	622,751	262,148	(14,794)
Beginning balance (in shares) at Dec. 31, 2018		86,679,575	80,608,685	(14,620,175)
Beginning balance at Dec. 31, 2018	682,589	$ 0	$ 1	$ (199,817)	618,674	270,471	(6,740)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	3,057
Ending balance (in shares) at Sep. 30, 2019		90,218,331	79,387,495	(14,620,175)
Ending balance at Sep. 30, 2019	673,943	$ 1	$ 0	$ (199,817)	632,759	273,528	(32,528)
Beginning balance (in shares) at Mar. 31, 2019		87,816,006	80,148,685	(14,620,175)
Beginning balance at Mar. 31, 2019	670,289	$ 0	$ 1	$ (199,817)	622,751	262,148	(14,794)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	2,740				2,740
Exercise of stock options (in shares)		85,038	139,270
Exercise of stock options	1,817				1,817
Conversion Class B to Class A common stock (in shares)		460	(460)
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)		753,800
Shares withheld for employee taxes upon conversion of restricted stock (in shares)		(105,349)
Shares withheld for employee taxes upon conversion of restricted stock	(1,400)				(1,400)
Other comprehensive income	(11,850)						(11,850)
Net income (loss)	4,538					4,538
Ending balance (in shares) at Jun. 30, 2019		88,549,955	80,287,495	(14,620,175)
Ending balance at Jun. 30, 2019	666,134	$ 0	$ 1	$ (199,817)	625,908	266,686	(26,644)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	5,721				5,721
Exercise of stock options (in shares)		169,023
Exercise of stock options	1,504				1,504
Conversion Class B to Class A common stock (in shares)		900,000	(900,000)
Conversion Class B to Class A common stock		$ 1	$ (1)
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)		614,795
Shares withheld for employee taxes upon conversion of restricted stock (in shares)		(15,442)
Shares withheld for employee taxes upon conversion of restricted stock	(374)				(374)
Other comprehensive income	(5,884)						(5,884)
Net income (loss)	6,842					6,842
Ending balance (in shares) at Sep. 30, 2019		90,218,331	79,387,495	(14,620,175)
Ending balance at Sep. 30, 2019	$ 673,943	$ 1	$ 0	$ (199,817)	$ 632,759	$ 273,528	$ (32,528)