Other Investments and Assets - Summary of Other Investments and Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Investments, All Other Investments [Abstract]
Cash surrender value of life insurance	$ 20,939	$ 20,866
Self-insured liability receivable	7,728	7,728
Workers’ compensation insurance security deposits	4,250	4,250
Other mutual funds	2,371	2,536
Other	5,521	5,294
Other investments and assets	$ 40,809	$ 40,674