Liability for Unpaid Claims - Summary of Liability for Unpaid Health Claims (Details) - Health Insurance [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Activity in the Liability for Unpaid Health Claims
Balance at beginning of period	$ 154,528	$ 146,865
Incurred related to:
Current year	151,230	134,542
Prior years	1,166	(5,001)
Total incurred	152,396	129,541
Paid related to:
Current year	60,055	55,130
Prior years	88,445	78,722
Total paid	148,500	133,852
Balance at end of period	$ 158,424	$ 142,554