Consolidated Statements of Shareholders' Equity Statement (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]
Balances, beginning at Dec. 31, 2011	$ 244,518	$ 206	$ (887)	$ 245,199	$ 0
Balances, beginning, shares at Dec. 31, 2011		61,038,507
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,328			12,318	10
Other comprehensive income, net of tax	355		355
Noncontrolling interest of PhaseLink	977	0			977
Acquisition of noncontrolling interest in PhaseLink	(932)	55			(987)
Share-based compensation	7,558	7,558
Payment of cash dividends	(12,072)			(12,072)
Repurchases of common stock, shares		(3,431,548)
Repurchases of common stock	(34,551)	(10,742)		(23,809)
Employee stock transactions, shares		599,980
Employee stock transactions	3,642	3,642
Tax effect of employee stock transactions	(185)	(185)
Purchases of common stock for withholding taxes on vested restricted stock, shares		(53,274)
Purchases of common stock for withholding taxes on vested restricted stock	(534)	(534)
Balances, ending at Dec. 31, 2012	221,104	0	(532)	221,636	0
Balances, ending, shares at Dec. 31, 2012		58,153,665
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	17,648			17,648	0
Other comprehensive income, net of tax	212		212
Share-based compensation	7,108	7,108
Payment of cash dividends	(8,219)			(8,219)
Repurchases of common stock, shares		(2,405,959)
Repurchases of common stock	(23,336)	(10,564)		(12,772)
Employee stock transactions, shares		774,403
Employee stock transactions	4,390	4,390
Tax effect of employee stock transactions	(122)	(122)
Purchases of common stock for withholding taxes on vested restricted stock, shares		(80,763)
Purchases of common stock for withholding taxes on vested restricted stock	(812)	(812)
Balances, ending at Dec. 31, 2013	217,973	0	(320)	218,293	0
Balances, ending, shares at Dec. 31, 2013	56,441,346	56,441,346
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	13,547			13,547	0
Other comprehensive income, net of tax	237		237
Share-based compensation	7,644	7,644
Payment of cash dividends	(11,299)			(11,299)
Repurchases of common stock, shares		(1,744,095)
Repurchases of common stock	(20,150)	(19,200)		(950)
Employee stock transactions, shares		1,868,599
Employee stock transactions	13,101	13,101
Tax effect of employee stock transactions	(40)	(40)
Purchases of common stock for withholding taxes on vested restricted stock, shares		(130,295)
Purchases of common stock for withholding taxes on vested restricted stock	(1,505)	(1,505)
Balances, ending at Dec. 31, 2014	$ 219,508	$ 0	$ (83)	$ 219,591	$ 0
Balances, ending, shares at Dec. 31, 2014	56,435,555	56,435,555