Stockholders' Equity and Stock-based Compensation Arrangements (Tables)

6 Months Ended

Jun. 30, 2013

Stockholders' Equity and Stock-based Compensation Arrangements

Schedule of compensation cost and the income tax benefit recognized for the plans

	Three Months Ended June 30,				Six Months Ended June 30,
	2013		2012		2013		2012
Compensation cost included in:
Basic income per share	$	0.01	$	0.01	$	0.01	$	0.01
Diluted income per share	$	0.01	$	0.01	$	0.01	$	0.01
Stock-based compensation expense	92		100		188		211
Income tax benefit	18		21		39		47

Schedule of information regarding the stock plans

	Number of Options		Weighted- Average Exercise Price		Weighted- Average Remaining Contract Life (in years)	Aggregate Intrinsic Value
Outstanding, January 1, 2013	641,050		$	22.12
Granted	—		—
Exercised	(18,500	)	17.99
Forfeited	—		—
Outstanding, June 30, 2013	622,550		$	22.24	4.6	$	5,011
Exercisable, June 30, 2013	582,550		$	23.00	4.4	$	4,261

Schedule of key assumptions used for fair value of options granted under the Purchase Plan

	Three Months Ended June 30,		Six Months Ended June 30,
	2013	2012	2013	2012
Risk-free interest rate	0.2%	0.2%	0.2%	0.2%
Weighted-average expected life of option feature (in years)	1.0	1.0	1.0	1.0
Expected volatility of underlying stock	28.7%	28.6%	28.7%	28.6%
Expected dividends	n/a	n/a	n/a	n/a
Weighted-average fair value of option feature	$5.98	$7.19	$5.98	$7.19

Schedule of information regarding the Purchase Plan

	Number of Options		Weighted- Average Exercise Price		Remaining Contract Life (in years)	Aggregate Intrinsic Value
Outstanding, January 1, 2013	12,641		$	20.56
Shares subscribed	15,140		20.56
Exercised	—		—
Forfeited	(1,310	)	20.56
Outstanding, June 30, 2013	26,471		$	20.56	0.1	$	249