Summary of Significant Accounting Policies Deferred Acquisition Costs and Cost of Customer Relationships Acquired (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred Policy Acquisition Costs and Cost of Customer Relationship Acquired [Abstract]
First year commissions, percentage of capitalized deferred acquisition costs	94.00%
New business expense, percentage of capitalized deferred acquisition costs	6.00%
Number of years of available premiums	50 years
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance at beginning of period	$ 163,692	$ 155,859	$ 145,101
Amortization of deferred policy acquisition costs	(28,515)	(23,400)	(21,083)
Deferred Policy Acquisition Cost, Amortization Expense, Effect of Adjustments to Estimated Gross Profit	(119)	129	(230)
Balance at end of period	$ 167,790	$ 163,692	$ 155,859