Note K - Accounting for Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Cash Settled RSUs [Member]

Notes Tables

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value (in thousands)
Non-vested CSRSUs at January 1, 2013		—		$	—
Granted		203,115		$	27.84
Cancelled		(2,816	)	$	27.03
Non-vested CSRSUs at December 31, 2013		200,299		$	28.23
Granted		416,432		$	39.12
Vested		(47,742	)	$	27.55
Cancelled		(31,870	)	$	32.12
Non-vested CSRSUs at December 31, 2014		537,119		$	36.36
Granted		121,015		$	39.35
Vested		(78,033	)	$	33.29
Cancelled		(133,438	)	$	38.14
Non-vested CSRSUs at December 31, 2015		446,663		$	37.18	$	15,883
CSRSUs expected to vest in the future		414,431		$	37.16	$	14,737

Restricted Stock Units (RSUs) [Member]

Notes Tables

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value (in thousands)
Non-vested RSUs at January 1, 2013		848,591		$	24.32
Granted		229,574		$	27.02
Vested		(288,258	)	$	24.28
Cancelled		(33,719	)	$	24.86
Non-vested RSUs at December 31, 2013		756,188		$	25.13
Granted		265,811		$	39.48
Vested		(333,321	)	$	24.73
Cancelled		(44,791	)	$	27.33
Non-vested RSUs at December 31, 2014		643,887		$	31.10
Granted		250,159		$	39.04
Vested		(233,899	)	$	26.85
Cancelled		(104,243	)	$	36.76
Non-vested RSUs at December 31, 2015		555,904		$	35.40	$	19,768
RSUs expected to vest in the future		512,897		$	35.40	$	18,239

Restricted Stock [Member]

Notes Tables

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

	Number of Shares			Weighted- Average Grant Date Fair Value
Non-vested restricted stock awards at January 1, 2013		36,139		$	22.41
Granted		—		$	—
Vested		(30,825	)	$	22.38
Forfeited		(5,314	)	$	22.58
Non-vested restricted stock awards at December 31, 2013		—		$	—

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

	Number of Shares			Weighted Average Exercise Price		Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2013		638,800		$	22.21
Exercised		(159,309	)	$	19.48
Granted		218,707		$	27.03
Forfeited/Expired		(3,646	)	$	24.84
Outstanding at December 31, 2013		694,552		$	24.34
Exercised		(85,063	)	$	21.53
Granted		166,861		$	40.68
Forfeited/Expired		(9,426	)	$	25.53
Outstanding at December 31, 2014		766,924		$	28.20
Exercised		(43,919	)	$	21.23
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2015		723,005		$	28.62	$	5,872
Vested plus expected to vest at December 31, 2015		664,824		$	28.35	$	5,530
Exercisable at December 31, 2015		540,287		$	26.35	$	5,263

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

			OPTIONS OUTSTANDING						OPTIONS EXERCISABLE
Range of Exercise Prices			Number Outstanding As of 12/31/1 5		Weighted Average Remaining Contractual Term		Weighted Average Exercise Price		Number Exercisable As of 12/31/1 5		Weighted Average Exercise Price
$ 9.05	–	$25.00		210,293		4.55	$	22.61		210,293	$	22.61
$25.01	–	$28.00		345,851		6.79	$	26.46		274,368	$	26.31
$28.01	–	$41.00		166,861		8.21	$	40.68		55,626	$	40.68
$ 9.05	to	$41.00		723,005		6.47	$	28.62		540,287	$	26.35

Schedule of Share-based Compensation, Nonemployee Director Stock Award Plan, Activity [Table Text Block]

For the Year ended December 31,	Number of Shares Granted		Weighted- Average Grant Date Fair Value
2013		5,133	$	35.06
2014		15,872	$	36.08
2015		18,109	$	35.62