Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, beginning of year	$ 197,202	$ 194,466	$ 185,910
Policy acquisition costs deferred	543,791	528,944	514,073
Amortization	(539,231)	(526,208)	(505,517)
Balance, end of year	$ 201,762	$ 197,202	$ 194,466