CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Benefits and settlement expenses, reinsurance ceded	$ 1,191,978	$ 1,242,797	$ 1,181,960
Other operating expenses, reinsurance ceded	$ 205,352	$ 222,963	$ 207,197