Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Leased Assets [Line Items]
Lease expiration date	Aug. 31, 2020
Operating lease term	15 years
Rent expense	$ 12,900,000	$ 12,900,000	$ 12,700,000
Tenant improvement allowance	10,300,000
Total sublease income	0
Future minimum lease payments under capital leases [Abstract]
2014	1,199,000
2015	66,000
2016	0
2017	0
2018	0
2019 and thereafter	0
Total minimum lease payments	1,265,000
Less amount representing interest	(34,000)
Present value of minimum lease payments	1,231,000
Less current portion	(1,166,000)
Future minimum lease payments, net of current portion	65,000
Future minimum lease payments under operating leases [Abstract]
2014	13,198,000
2015	11,781,000
2016	10,764,000
2017	10,198,000
2018	10,707,000
2019 and thereafter	33,262,000
Total minimum lease payments	89,910,000
Minimum [Member]
Operating Leased Assets [Line Items]
Lease expiration date	Feb. 14, 2014
Maximum [Member]
Operating Leased Assets [Line Items]
Lease expiration date	Oct. 31, 2020
Corporate Headquarters and Call Center [Member]
Operating Leased Assets [Line Items]
Area of leased property (in square feet)	264,000
Corporate Headquarters and Call Center [Member] | Minimum [Member]
Operating Leased Assets [Line Items]
Rent expense	4,200,000
Corporate Headquarters and Call Center [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Rent expense	$ 6,300,000
Other Call Center Locations [Member]
Operating Leased Assets [Line Items]
Area of leased property (in square feet)	160,000
Operations Support and Training Offices [Member]
Operating Leased Assets [Line Items]
Area of leased property (in square feet)	66,000
Office Space in Chandler [Member]
Operating Leased Assets [Line Items]
Area of leased property (in square feet)	92,000