Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Paid-in Capital in Excess of par	Accumulated Other Comprehensive Income	Retained Earnings	Total
Balances at Dec. 31, 2014	$ 83	$ 42,076		$ 174,489	$ 216,648
Balances (in shares) at Dec. 31, 2014	8,346
Increase (Decrease) in Shareholders' Equity
Net income				3,423	3,423
Net unrealized loss from derivative instruments, net of tax benefit			$ (200)		(200)
Shares repurchased	$ (2)	(3,648)			(3,650)
Shares repurchased (in shares)	(208)
Shares issued under stock compensation plans	$ 3	516			519
Shares issued under stock compensation plans (in shares)	207
Cancellation of restricted stock units in satisfaction of withholding tax	$ (1)	(1,100)			(1,101)
Cancellation of restricted stock units in satisfaction of withholding tax (in shares)	(64)
Stock-based compensation, net of forfeitures		2,961			2,961
Tax benefit on disqualified disposition of shares		75			75
Balances at Sep. 30, 2015	$ 83	40,880	(200)	177,912	218,675
Balances (in shares) at Sep. 30, 2015	8,281
Balances at Dec. 31, 2015	$ 75	28,720	(521)	180,949	209,223
Balances (in shares) at Dec. 31, 2015	7,548
Increase (Decrease) in Shareholders' Equity
Net income				11,362	11,362
Net unrealized loss from derivative instruments, net of tax benefit			(1,322)		(1,322)
Shares repurchased	$ (10)	(25,012)			(25,022)
Shares repurchased (in shares)	(1,058)
Shares issued under stock compensation plans	$ 1	154			155
Shares issued under stock compensation plans (in shares)	127
Cancellation of restricted stock units in satisfaction of withholding tax		(866)			(866)
Cancellation of restricted stock units in satisfaction of withholding tax (in shares)	(41)
Stock-based compensation, net of forfeitures		2,755			2,755
Tax benefit on disqualified disposition of shares		189			189
Balances at Sep. 30, 2016	$ 66	$ 5,940	$ (1,843)	$ 192,311	$ 196,474
Balances (in shares) at Sep. 30, 2016	6,576