Other Operating Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Operating Expenses [Abstract]
Amortization of gross deferred policy acquisition costs		$ 78,105	$ 70,574	$ 51,597
Other underwriting expenses		46,638	37,230	41,692
Reinsurance ceded credits		(23,124)	(23,187)	(33,512)
Total underwriting expenses		101,619	84,617	59,777
Operating expenses of non-insurance companies		32,406	28,977	29,685
Goodwill impairment charge	$ 3,152	3,152	0	0
Total other operating expenses		$ 137,177	$ 113,594	$ 89,462