Employee Pension Plans (Details) (Defined benefit pension plan, USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Defined benefit pension plan
Summary of net periodic benefit cost
Interest cost	$ 1,030,000	$ 917,000	$ 2,060,000	$ 1,833,000
Expected return on plan assets	(1,192,000)	(1,120,000)	(2,384,000)	(2,240,000)
Amortization of net loss	1,077,000	1,544,000	2,154,000	3,088,000
Net periodic benefit cost	915,000	1,341,000	1,830,000	2,681,000
Company contribution			1,500,000	600,000
Expected contributions remainder of current fiscal year			$ 3,500,000