Cash Deposits and Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Insurance collateral deposits	$ 3,517	$ 3,767
Excess loss fund	1,662	2,284
Accumulated interest income	736	814
State collateral deposits	61	57
Materials and supplies	227	273
Other	36	37
Total	$ 6,239	$ 7,232

Carrying amount of assets as of the balance sheet date pertaining to amounts paid by the insured (including a ceding company) under insurance or reinsurance contracts for which insurance risk is not transferred.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99397363&loc=d3e9420-108338

Name:	us-gaap_DepositContractsAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant