Loss Reserves - Reconciliation of Beginning and Ending Balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Loss Reserve [Roll Forward]
Reserve at beginning of period	$ 674,019	$ 985,635
Less reinsurance recoverable	33,328	48,474
Net reserve at beginning of period	640,691	937,161
Losses and LAE incurred in respect of delinquency notices received in:
Current year	47,488	59,070
Prior years	(8,425)	(35,220)
Total losses incurred	39,063	23,850
Losses and LAE paid in respect of delinquency notices received in:
Current year	0	95
Prior years	56,365	81,983
Reinsurance terminations	0	236
Total losses paid	56,365	82,314
Net reserve at end of period	623,389	878,697
Plus reinsurance recoverables	31,875	45,474
Reserve at end of period	$ 655,264	$ 924,171