Defined Contribution, Bonus, and Profit Sharing (Tables)

12 Months Ended

Dec. 31, 2017

Defined Contribution, Bonus, and Profit Sharing [Abstract]

Schedule of Costs of Retirement Plans [Table Text Block]

The expense for our defined contribution plans was as follows:

	Year Ended December 31,
	2017		2016		2015
	(in thousands)
Defined contribution plans expense	$	11,709	$	7,941	$	6,579

Schedule of Bonus and Profit Sharing Expenses [Table Text Block]

Bonus and profit sharing plans and award expense was as follows:

	Year Ended December 31,
	2017		2016		2015
	(in thousands)
Bonus and profit sharing plans and award expense	$	40,005	$	43,377	$	14,192