Stock Options And Employee Stock Purchase Plan (Tables)

12 Months Ended

Dec. 31, 2012

Stock Options Activity

Stock option activity for the years ended December 31, 2012, 2011 and 2010 is summarized as follows:

	Number of Shares		Weighted-Average Exercise Price	Weighted-Average Remaining Contractual Life (In Years)	Aggregate Intrinsic Value
Options outstanding at December 31, 2009	4,480,591		$13.17
Granted	167,967		$23.13
Exercised	(816,552	)	$9.18
Canceled	(37,612	)	$20.26
Options outstanding at December 31, 2010	3,794,394		$14.40
Granted	163,319		$29.42
Exercised	(1,820,678	)	$7.92
Canceled	(49,340	)	$24.76
Options outstanding at December 31, 2011	2,087,695		$20.99
Granted	67,000		$27.26
Exercised	(357,234	)	$15.81
Canceled	(32,000	)	$31.34
Options outstanding at December 31, 2012	1,765,461		$22.08	5.1	$15,684,163
Exercisable at December 31, 2012	1,132,365		$21.94	4.0	$10,451,569
Vested and expected to vest at December 31, 2012	1,664,406		$21.95	4.9	$15,042,947

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]

The following table summarizes information concerning outstanding and exercisable options as of December 31, 2012:

	Options Outstanding			Exercisable Options
Range of Exercise Prices	Number Outstanding December 31, 2012	Weighted Average Remaining Contractual Life	Weighted Average Exercise Price	Number Exercisable December 31, 2012	Weighted Average Exercise Price
8.09	2,439	0.44 years	8.09	2,439	8.09
9.55	200,000	1.23 years	9.55	200,000	9.55
11.43 - 15.65	17,956	2.70 years	14.30	13,956	14.47
17.19	309,280	6.18 years	17.19	77,800	17.19
18.77	239,000	2.67 years	18.77	239,000	18.77
20.15 - 21.67	240,301	5.80 years	21.12	145,712	21.07
21.88 - 25.09	179,666	7.41 years	23.34	57,790	22.86
25.93 - 29.34	262,319	6.63 years	28.53	124,168	28.56
29.53 - 32.45	194,500	5.67 years	31.92	151,500	32.41
33.51 - 34.73	120,000	4.46 years	33.66	120,000	33.66
$8.09 - $34.73	1,765,461	5.07 years	22.08	1,132,365	21.94

Assumptions To Estimate Fair Value Of Stock Options

The weighted-average fair values of stock options granted have been estimated utilizing the following assumptions:

	Year Ended December 31,
	2012	2011	2010
Risk-free interest rate	1.1%	2.3%	2.6%
Expected term (in years)	5.7	6.5	6.5
Dividend yield	3.2%	2.6%	—	%
Expected volatility	41.6%	41.8%	44.7%

Allocation Of Share-Based Compensation Expense

The following table represents share-based compensation expense included in cost of revenues and operating expenses in the consolidated statements of income for the years ended December 31, 2012, 2011 and 2010 (in thousands):

	Year Ended December 31,
	2012		2011		2010
Cost of revenues	$	844	$	982	$	1,217
Operating expenses:
Sales and marketing	1,543		1,431		1,826
Research, development and engineering	459		477		815
General and administrative	6,286		6,103		7,079
	$	9,132	$	8,993	$	10,937

Restricted Stock [Member]

Restricted Stock And Restricted Stock Unit Award Activity

Restricted stock award activity for the year ended December 31, 2012 is set forth below:

	Shares		Weighted-Average Grant-Date Fair Value
Nonvested at January 1, 2012	742,683		$	20.87
Granted	299,044		27.68
Vested	(202,352	)	21.34
Canceled	(10,900	)	30.92
Nonvested at December 31, 2012	828,475		$	23.08

Restricted Stock Units (RSUs) [Member]

Restricted Stock And Restricted Stock Unit Award Activity

Restricted stock unit activity for the year ended December 31, 2012 is set forth below:

	Number of Shares		Weighted-Average Remaining Contractual Life (in Years)	Aggregate Intrinsic Value
Outstanding at January 1, 2011	17,500
Granted	17,000
Vested	(1,750	)
Canceled	—
Outstanding at December 31, 2011	32,750
Granted	91,166
Vested	(1,700	)
Canceled	(6,750	)
Outstanding at December 31, 2012	115,466		2.7	$	3,533,260
Vested and expected to vest at December 31, 2012	76,459		2.4	$	2,339,659