Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Shares [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2015	$ 290,311	$ 1,866	$ 232,126	$ 62,551	$ (6,232)
Balance, Shares at Dec. 31, 2015		18,659,696
Cumulative effect adjustment from adoption | ASU 2016-09 [Member]	604		2,032	(1,428)
Net income	3,056			3,056
Other comprehensive income (loss), net of tax	(348)				(348)
Share-based compensation	15,966		15,966
Common shares issued	17,313	$ 71	17,242
Common shares issued, Shares		713,140
Retirement of repurchased common stock	$ (63,425)	$ (154)	(63,271)
Retirement of repurchased common stock, Shares	(1,544,681)	(1,544,681)
Ending Balance at Dec. 31, 2016	$ 263,477	$ 1,783	204,095	64,179	(6,580)
Balance, Shares at Dec. 31, 2016		17,828,155
Net income	6,223			6,223
Other comprehensive income (loss), net of tax	10,367				10,367
Share-based compensation	12,557		12,557
Common shares issued	3,984	$ 45	3,939
Common shares issued, Shares		450,678
Ending Balance at Dec. 31, 2017	$ 296,608	$ 1,828	220,591	70,402	3,787
Balance, Shares at Dec. 31, 2017	18,278,833	18,278,833
Cumulative effect adjustment from adoption | ASU 2016-16 [Member]	$ (1,900)
Ending Balance (ASU 2014-09 [Member]) at Jan. 01, 2018	301,369
Beginning Balance at Dec. 31, 2017	$ 296,608	$ 1,828	220,591	70,402	3,787
Balance, Shares at Dec. 31, 2017	18,278,833	18,278,833
Cumulative effect adjustment from adoption | ASU 2014-09 [Member]	$ 4,761			4,761
Cumulative effect adjustment from adoption | ASU 2016-16 [Member]	(1,896)			(1,896)
Net income	13,811			13,811
Other comprehensive income (loss), net of tax	(491)				(491)
Share-based compensation	18,930		18,930
Common shares issued	3,674	$ 30	3,644
Common shares issued, Shares		300,855
Ending Balance at Dec. 31, 2018	$ 335,397	$ 1,858	$ 243,165	$ 87,078	$ 3,296
Balance, Shares at Dec. 31, 2018	18,579,688	18,579,688