Taxation (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets
Tax loss and credit carryforwards	$ 62,643	$ 51,620
Reserve for claims and claim expenses	13,992	26,265
Deferred interest expense	11,320	18,408
Unearned premiums	9,436	7,496
Deferred underwriting results	3,407	0
Investments	0	3,269
Accrued expenses	2,641	9,386
Deferred tax assets	103,439	116,444
Deferred tax liabilities
Deferred acquisition expenses	(12,343)	(7,485)
Amortization and depreciation	(3,340)	(7,097)
Investments	(1,047)	0
Deferred underwriting results	0	(2,964)
Deferred tax liabilities	(16,730)	(17,546)
Net deferred tax asset before valuation allowance	86,709	98,898
Valuation allowance	(30,016)	(18,776)
Net deferred tax asset	$ 56,693	$ 80,122