Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Current expense	$ 12,959	$ 10,640
Deferred expense	4,158	13,398
Total income tax provision	$ 17,117	$ 24,038
Reconciliation between the statutory federal income tax rate and the effective income tax rate from continuing operations
Statutory federal income tax rate	35.00%	35.00%
Investment income not subject to federal tax	(3.30%)	(2.30%)
Tax credits	(0.80%)	(16.30%)
State income taxes, net of federal benefit	1.80%	2.30%
Other, net	0.30%	0.90%
Effective income tax rate	33.00%	19.60%
Reconciliation of unrecognized tax benefits
Increase in unrecognized tax benefit	$ 1,994	$ 1,843
Additional decrease to unrecognized tax benefits	$ 7,000	$ 9,000