Employee Retirement Plans (Details Textual) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Actual employer contributions to defined benefit plans	$ 2.4	$ 4.7	$ 3.1	$ 8.1
Expected full year contributions by the employer to defined benefit plans			4.8
Contributions to multiemployer plan	$ 0.6	$ 0.6	1.1	$ 1.3
Expected full year contributions by the employer to the multiemployer plan			$ 2.3