Retirement Plans (Defined Contribution Plans) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	$ 672	$ 917	$ 1,473	$ 1,741
UNITED STATES
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	445	747	1,137	1,429
CANADA
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	67	55	118	114
UNITED KINGDOM
Defined Contribution Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	$ 160	$ 115	$ 218	$ 198