Goodwill and Other Intangible Assets - Identifiable Intangible Assets Subject to Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Non-compete agreements	$ 29,081	$ 36,581
Total other intangibles, gross	14,672	19,473
Less accumulated amortization	14,409	17,108
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Non-compete agreements	29,081	35,781
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Non-compete agreements	$ 0	$ 800