Significant Accounting Policies (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017
Impact of adoption on our Statement of Financial Position
Deferred tax asset	$ 29,055		$ 29,578
Contract liability	48,861		48,514
Retained earnings	2,129,100		2,102,527	$ 2,140,853
Calculated under revenue guidance in effect before ASC 606
Impact of adoption on our Statement of Financial Position
Deferred tax asset	18,794			19,390
Retained earnings	2,167,700			$ 2,140,853
Difference between revenue guidance in effect before and after ASC 606 | Accounting Standards Update 2014-09
Impact of adoption on our Statement of Financial Position
Deferred tax asset	10,261		10,188
Contract liability	48,861		48,514
Retained earnings	(38,600)		$ (38,326)
Policy issuance and renewal services
Impact of adoption on our Statement of Operations
Management fee revenue, gross	407,236
Less: change in allowance for management fee returned on cancelled policies	(1,258)
Management fee revenue, net	405,978	$ 392,058
Cost of operations	348,630	$ 332,376
Policy issuance and renewal services | Calculated under revenue guidance in effect before ASC 606
Impact of adoption on our Statement of Operations
Management fee revenue, gross	420,699
Less: change in allowance for management fee returned on cancelled policies	(1,300)
Management fee revenue, net	419,399
Policy issuance and renewal services | Difference between revenue guidance in effect before and after ASC 606 | Accounting Standards Update 2014-09
Impact of adoption on our Statement of Operations
Management fee revenue, gross	(13,463)
Less: change in allowance for management fee returned on cancelled policies	42
Management fee revenue, net	(13,421)
Administrative services
Impact of adoption on our Statement of Operations
Management fee revenue, gross	13,088
Less: change in allowance for management fee returned on cancelled policies	(14)
Management fee revenue, net	13,074
Administrative services reimbursement revenue	145,963
Total revenue allocated to administrative services	159,037
Cost of operations	145,963
Administrative services | Difference between revenue guidance in effect before and after ASC 606 | Accounting Standards Update 2014-09
Impact of adoption on our Statement of Operations
Management fee revenue, gross	13,088
Less: change in allowance for management fee returned on cancelled policies	(14)
Management fee revenue, net	13,074
Administrative services reimbursement revenue	145,963
Total revenue allocated to administrative services	159,037
Cost of operations	$ 145,963