Segments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 segments	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of Operating segments			5
Approximate percentage of segment revenue charged as an allocation of corporate overhead			5.00%		5.00%
Reversal of a lawsuit accrual	$ (13,400)	$ 0	$ (28,400)	$ 35,500
All Other Segments
Segment Reporting Information [Line Items]
Reversal of a lawsuit accrual	10,400		10,400
Sales and Lease Ownership
Segment Reporting Information [Line Items]
Reversal of a lawsuit accrual			35,500
Pending Legal and Regulatory Contingency
Segment Reporting Information [Line Items]
Reversal of a lawsuit accrual			(28,400)
Retirement Expenses
Segment Reporting Information [Line Items]
Reversal of a lawsuit accrual			$ 4,900