Significant Accounting Policies and Recent Accounting Pronouncements ASU 2014-09 Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Service expense									$ 1,401,152	$ 1,253,608	$ 1,197,211
General and administrative expense									67,244	77,093	69,907
Operating (loss) income	$ 7,554	$ 16,987	$ (3,250)	$ 3,441	$ (693)	$ 9,435	$ 3,431	$ 12,103	24,732	24,276	37,484
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Service expense									1,401,152	1,253,608	1,197,211
General and administrative expense									67,244	77,093	69,907
Operating (loss) income	$ 7,554	$ 16,987	$ (3,250)	$ 3,441	$ (693)	$ 9,435	$ 3,431	$ 12,103	$ 24,732	24,276	$ 37,484
Pro Forma
Accounting Policies [Abstract]
Service expense										1,400,453
General and administrative expense										1,300,091
Operating (loss) income										24,276
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Service expense										1,400,453
General and administrative expense										1,300,091
Operating (loss) income										$ 24,276