Inventory (Schedule Of Inventory Writedowns By Segment) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Inventory [Line Items]
Inventory write-down	$ 10,003	$ 8,802	$ 6,136
Agency [Member]
Inventory [Line Items]
Inventory write-down	5,888	3,954	4,203
Principal [Member]
Inventory [Line Items]
Inventory write-down	4,115	4,848	1,933
Principal Segment Component [Member] | Principal [Member]
Inventory [Line Items]
Inventory write-down	$ 700	$ 4,400	$ 400