Note 3 - Share-based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Restricted share units:
Pretax compensation expense	$	9,844	$	8,873	$	18,435	$	17,010
Tax benefit		2,559		3,314		4,793		5,596
Restricted share unit expense, net of tax	$	7,285	$	5,559	$	13,642	$	11,414
Performance share units:
Pretax compensation expense	$	4,121	$	3,067	$	7,566	$	6,100
Tax benefit		1,071		1,146		1,967		2,007
Performance share unit expense, net of tax	$	3,050	$	1,921	$	5,599	$	4,093