Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock	Paid-in Capital in Excess of par	Retained Earnings	Accumulated Other Comprehensive Income	Total
Balances at Dec. 31, 2014		$ 83	$ 42,076	$ 174,489		$ 216,648
Balances (in shares) at Dec. 31, 2014		8,346,000
Increase (Decrease) in Shareholders' Equity
Net income				6,460		6,460
Net unrealized gain from derivative instruments, net of tax expense					$ (521)	(521)
Shares repurchased		$ (9)	(16,491)			(16,500)
Shares repurchased (in shares)		(912,000)
Shares issued under stock compensation plans		$ 2	516			518
Shares issued under stock compensation plans (in shares)		205,000
Cancellation of restricted stock units in satisfaction of withholding tax		$ (1)	(1,557)			(1,558)
Cancellation of restricted stock units in satisfaction of withholding tax (in shares)		(91,000)
Stock-based compensation, net of forfeitures			4,150			4,150
Tax benefit on disqualified disposition of shares			26			26
Balances at Dec. 31, 2015		$ 75	28,720	180,949	(521)	209,223
Balances (in shares) at Dec. 31, 2015		7,548,000
Increase (Decrease) in Shareholders' Equity
Net income				14,069		14,069
Net unrealized loss from currency translation adjustment, net of tax benefit					(568)	(568)
Net unrealized gain from derivative instruments, net of tax expense					44	44
Shares repurchased		$ (12)	(28,946)			(28,958)
Shares repurchased (in shares)		(1,212,000)
Shares issued under stock compensation plans		$ 1	154			155
Shares issued under stock compensation plans (in shares)		127,000
Cancellation of restricted stock units in satisfaction of withholding tax			(1,369)			(1,369)
Cancellation of restricted stock units in satisfaction of withholding tax (in shares)		(61,000)
Stock-based compensation, net of forfeitures			3,717			3,717
Issuance of preferred stock	$ 19,752
Accretion of preferred stock issuance costs	8			(8)		(8)
Preferred stock dividends paid				(281)		(281)
Tax benefit on disqualified disposition of shares			236			236
Balances at Dec. 31, 2016	$ 19,760	$ 64	2,512	194,729	(1,045)	$ 196,260
Balances (in shares) at Dec. 31, 2016	1,000,000	6,402,000
Increase (Decrease) in Shareholders' Equity
Issuance of preferred stock (in shares)	1,000,000					1,000
Net income				62,158		$ 62,158
Net unrealized loss from currency translation adjustment, net of tax benefit					584	584
Net unrealized gain from derivative instruments, net of tax expense					687	687
Shares repurchased		$ (2)	(3,544)			(3,546)
Shares repurchased (in shares)		(155,000)
Shares issued under stock compensation plans		$ 2	175			177
Shares issued under stock compensation plans (in shares)		216,000
Cancellation of restricted stock units in satisfaction of withholding tax			(1,094)			(1,094)
Cancellation of restricted stock units in satisfaction of withholding tax (in shares)		(44,000)
Stock-based compensation, net of forfeitures			4,270			4,270
Issuance of preferred stock	$ 29,665
Accretion of preferred stock issuance costs	46			(46)		(46)
Preferred stock dividends paid				(1,813)		(1,813)
Other				1,273		1,273
Balances at Dec. 31, 2017	$ 49,471	$ 64	$ 2,319	$ 256,301	$ 226	$ 258,910
Balances (in shares) at Dec. 31, 2017	2,500,000	6,419,000
Increase (Decrease) in Shareholders' Equity
Issuance of preferred stock (in shares)	1,500,000					2,500