Disclosures About Fair Value - Fair Value of Assets and Liabilities on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets
Available-for-sale Securities	$ 3,354	$ 25,071
Fair Value, Measurements, Recurring
Assets
Available-for-sale equity securities	2,457	20,689
Available-for-sale debt securities	897	4,382
Available-for-sale Securities	3,354	25,071
Fair Value, Measurements, Recurring | Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets
Available-for-sale equity securities	2,072	12,545
Available-for-sale debt securities	897	4,382
Available-for-sale Securities	2,969	16,927
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets
Available-for-sale equity securities	385	8,144
Available-for-sale debt securities
Available-for-sale Securities	$ 385	$ 8,144