Schedule II - Valuation and Qualifying Accounts and Reserves - Valuation Allowances and Reserves (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Insurance and Claims Accruals [Member]
Balance at Beginning of Year		$ 26,177	$ 19,440	$ 16,235
Charged to Costs and Expenses		56,122	53,609	49,614
Deductions	[1]	(54,196)	(46,872)	(46,409)
Balance at End of Year		28,103	26,177	19,440
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Balance at Beginning of Year		300	275	305
Charged to Costs and Expenses		163	33	88
Deductions	[2]	(115)	(8)	(118)
Balance at End of Year		$ 348	$ 300	$ 275

[1] Claims payments

[2] Write-off of bad debts, net of recoveries