Employee Retirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Benefits earned during the period	$ 410	$ 240	$ 821	$ 631
Interest cost on projected benefit obligation	674	630	1,347	1,292
Expected return on plan assets	(592)	(598)	(1,184)	(1,171)
Net amortization and deferral	445	156	890	354
Net pension expense	$ 937	$ 428	$ 1,874	$ 1,106