Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Contingency [Line Items]
Current (benefit) expense	$ (15,771)	$ 12,959
Deferred expense	29,324	4,158
Total income tax provision	$ 13,553	$ 17,117
Reconciliation between the statutory federal income tax rate and the effective income tax rate from continuing operations
Statutory federal income tax rate	21.00%	35.00%
Investment income not subject to federal tax	(2.20%)	(3.30%)
Tax credits	(0.60%)	(0.80%)
State income taxes, net of federal benefit	2.80%	1.80%
Other, net	0.80%	0.30%
Effective income tax rate	21.80%	33.00%
Reconciliation of unrecognized tax benefits
Increase (decrease) in unrecognized tax benefit	$ 962	$ (1,994)
Minimum
Reconciliation of unrecognized tax benefits
Additional increase to unrecognized tax benefits	3,000
Maximum
Reconciliation of unrecognized tax benefits
Additional increase to unrecognized tax benefits	$ 4,000