Sch II - Condensed Financial Information on Registrant Notes - Dividends and debt (Details) - Parent Company [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries (eliminated in consolidation)	$ 85,900	$ 50,000	$ 45,700
Dividends in form of cash [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries (eliminated in consolidation)	$ 85,900	$ 50,000	$ 45,700