Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($)	Common Stock [Member]	Class C Special Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss, Net of Tax [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2018	$ 1	$ 0	$ 186,812,000	$ (659,000)	$ (379,000)	$ 11,488,000	$ 197,263,000
Balance (in shares) at Dec. 31, 2018	11,863			11
Cumulative-effect of change in accounting principle	$ 0	0	0	$ 0	0	2,000	2,000
Stock-based Compensation Expense	0	0	1,710,000	0	0	0	1,710,000
Changes in Treasury Stock Related to Stock-based Compensation Arrangements	0	0	0	$ (308,000)	0	0	(308,000)
Changes in Treasury Stock Related to Stock-based Compensation Arrangements (in shares)				6,000
Issuance of Common Shares upon Stock Option and ESPP Exercise	$ 0	0	2,416,000	$ 0	0	0	2,416,000
Issuance of Common Shares upon Stock Option and ESPP Exercise (in shares)	55			0
Issuance of Restricted Stock Awards	$ 0	0	(967,000)	$ 967,000	0	0	0
Issuance of Restricted Stock Awards (in shares)	106			(15)
Change in Fair Value of Interest Rate Swap, Net of Tax	$ 0	0	0	$ 0	(1,820,000)	0	(1,820,000)
Net (Loss)/Income	0	0	0	0	0	449,000	449,000
Balance at Mar. 31, 2019	$ 1	0	189,971,000	$ 0	(2,199,000)	11,939,000	199,712,000
Balance (in shares) at Mar. 31, 2019	12,024			2
Balance at Dec. 31, 2019	$ 1	0	200,800,000	$ (723,000)	(4,871,000)	17,584,000	212,791,000
Balance (in shares) at Dec. 31, 2019	12,105			15
Cumulative-effect of change in accounting principle	$ 0	0	0	$ 0	0	(8,000)	(8,000)
Stock-based Compensation Expense	0	0	2,424,000	0	0	0	2,424,000
Changes in Treasury Stock Related to Stock-based Compensation Arrangements	0	0	0	$ (488,000)	0	0	(488,000)
Changes in Treasury Stock Related to Stock-based Compensation Arrangements (in shares)				13,000
Issuance of Common Shares upon Stock Option and ESPP Exercise	$ 0	0	281,000	$ 0	0	0	281,000
Issuance of Common Shares upon Stock Option and ESPP Exercise (in shares)	7			0
Change in Fair Value of Interest Rate Swap, Net of Tax	$ 0	0	0	$ 0	(6,818,000)	0	(6,818,000)
Net (Loss)/Income	0	0	0	0	0	(7,011,000)	(7,011,000)
Balance at Mar. 31, 2020	$ 1	$ 0	$ 203,505,000	$ (1,211,000)	$ (11,689,000)	$ 10,565,000	$ 201,171,000
Balance (in shares) at Mar. 31, 2020	12,112			28