Debt - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Debt Instrument
Interest Expense, Debt	$ 11,780	$ 12,999
Finance lease liabilities
Debt Instrument
Interest Expense, Debt	371	294
Other
Debt Instrument
Interest Expense, Debt	1,385	1,990
Senior Notes | 6.75% Notes
Debt Instrument
Interest Expense, Debt	5,906	5,906
Senior Notes | 7.625% Notes
Debt Instrument
Interest Expense, Debt	1,906	1,906
Surplus Notes | Subordinated Debentures
Debt Instrument
Interest Expense, Debt	997	1,163
Credit Agreement | JPMorgan Chase, N.A.
Debt Instrument
Interest Expense, Debt	0	1,211
2019 Credit Agreement | JPMorgan Chase, N.A.
Debt Instrument
Interest Expense, Debt	$ 1,215	$ 529