INVESTMENTS Debt and Short-term Investments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Other invested assets
Other investments	$ 36,562		$ 36,562		$ 33,808
Cash and Short-term Investments
Cash	34,102	$ 21,355	34,102	$ 21,355	24,271	$ 18,269
Short-term investments, at cost which approximates fair value					9,980
Investment In Low Income Housing Tax Credit Partnership Net Of Amortization Member
Other invested assets
Other investments	14,500		14,500		$ 15,500
Total tax benefit on investments in housing tax credit partnership	600	$ 600	1,100	$ 1,300
Qualified Affordable Housing Project Investments, Commitment	2,000		2,000
Investment in Federal Home Loan Bank Stock [Member]
Other invested assets
Available-for-sale Securities Pledged as Collateral	16,800		16,800
Federal Home Loan Bank Borrowings, Fair Value Disclosure	0		0
Investment in Private Funds [Member]
Other invested assets
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 28,200		$ 28,200