Other Investments and Assets - Summary of Other Investments and Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Investments All Other Investments [Abstract]
Cash surrender value of life insurance	$ 23,981	$ 23,815
Self-insured liability receivable	9,176	9,176
Contract costs	4,376	3,461
Other mutual funds	3,055	2,517
Other	2,700	3,941
Other investments and assets	$ 43,288	$ 42,910