Retirement Plans (Defined Contribution Plans) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	$ 799	$ 824
UNITED STATES
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	691	682
CANADA
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	50	59
UNITED KINGDOM
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	$ 58	$ 83