Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Expense

The following table discloses the amount of stock based compensation expense for the three and six-month periods ended June 30, 2012 and 2013:

	Three months ended June 30				Six months ended June 30
	2012		2013		2012		2013
Stock options	$	864	$	1,002	$	1,643	$	1,973
Restricted stock units		292		280		604		559
Performance stock units		1,124		1,361		1,424		1,929
Total stock based compensation	$	2,280	$	2,643	$	3,671	$	4,461

Weighted-Average Assumptions

The fair value of these options was estimated at the date of grant using a Black-Scholes option pricing model with the following weighted-average assumptions:

	2012			2013
Risk-free interest rate		1.2	%		1.2	%
Dividend yield		2.7	%		1.7	%
Expected volatility of the Company’s common stock		0.644			0.646
Expected life in years		6.0			6.0

Details of Stock Option Activity

The following table provides details of the stock option activity for the six months ended June 30, 2013:

	Number of Shares
Outstanding at January 1, 2013		1,486,351
Granted		330,639
Exercised		(78,981	)
Expired		—
Cancelled		(6,568	)
Outstanding at June 30, 2013		1,731,441
Exercisable		914,480

Details of Restricted Stock Unit Activity

The following table provides details of the nonvested RSU activity for the six months ended June 30, 2013:

	Number of Restricted Units
Nonvested at January 1, 2013		110,871
Granted		1,000
Vested		(25,415	)
Accrued dividend equivalents		745
Nonvested at June 30, 2013		87,201

Schedule of Nonvested PSUs Under Long-Term Incentive Plans

The following table provides details of the nonvested PSUs under the Company’s Long-Term Incentive Plans:

Performance stock units outstanding at January 1, 2013	216,623
Adjustments to outstanding units	2,077
Accrued dividend equivalents	1,659
Performance stock units outstanding at June 30, 2013	220,359