Schedule II - Condensed Financial Information of Registrant - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Fixed maturities available for sale, at fair value	$ 2,613,406	$ 2,760,287
Short-term investments	442,084	119,236
Investment in unconsolidated subsidiaries	340,906	311,908
Cash and cash equivalents	117,347	241,100	$ 197,040	$ 129,383
Other assets	96,004	103,966
Total Assets	5,065,181	4,906,021
Liabilities
Dividends declared and not yet paid	265,659	69,447	167,744
Other liabilities	422,285	202,303
Debt less debt issuance costs	448,202	347,858
Total Liabilities	3,266,479	2,947,667
Shareholders’ Equity:
Common stock	627	625
Total Shareholders’ Equity	1,798,702	1,958,354	2,157,944	2,394,414
Total Liabilities and Shareholders’ Equity	5,065,181	4,906,021
Parent Company
Assets
Investment in subsidiaries, at equity	1,908,663	2,026,247
Fixed maturities available for sale, at fair value	267,412	202,501
Short-term investments	279,510	16,716
Investment in unconsolidated subsidiaries	845	0
Cash and cash equivalents	31,330	103,292	87,200	$ 37,459
Due from subsidiaries	185	0
Other assets	33,350	46,146
Total Assets	2,521,295	2,394,902
Liabilities
Due to subsidiaries	0	14,803
Dividends declared and not yet paid	265,659	69,447	$ 167,744
Other liabilities	8,733	4,440
Debt less debt issuance costs	448,202	347,858
Total Liabilities	722,594	436,548
Shareholders’ Equity:
Common stock	627	625
Other shareholders’ equity, including unrealized gains (losses) on securities of subsidiaries	1,798,074	1,957,729
Total Shareholders’ Equity	1,798,701	1,958,354
Total Liabilities and Shareholders’ Equity	$ 2,521,295	$ 2,394,902