Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Investments, Owned, Federal Income Tax Note [Line Items]
Current	$ 18,062	$ 46,389	$ 71,658	$ 72,291
Deferred	11,728	(13,102)	48,666	(5,132)
Total income tax provision	29,790	33,287	120,324	67,159
Reconciliation between the statutory federal income tax rate and the effective income tax rate from continuing operations
Statutory federal income tax rate (as a percent)			35.00%	35.00%
Income tax effect of investment income not subject to federal tax (as a percent)			(2.00%)	(2.70%)
Income tax effect of tax credits (as a percent)			(0.30%)	(1.40%)
Income tax effect of state income taxes, net of federal benefit (as a percent)			1.50%	2.00%
Income tax effect of other, net (as a percent)			0.10%	0.40%
Effective income tax rate (as a percent)			34.30%	33.30%
Reconciliation of unrecognized tax benefits
Amount of unrecognized tax benefits if recognized, would impact the annual effective tax rate	1,401	12,965	1,401	12,965
Minimum
Reconciliation of unrecognized tax benefits
Additional increase to unrecognized tax benefits	6,000		6,000
Maximum
Reconciliation of unrecognized tax benefits
Additional increase to unrecognized tax benefits	$ 7,000		$ 7,000