Redemption Price Percentage (Detail) - 6.0% Senior Notes Due 2022	12 Months Ended
	Dec. 31, 2016
2017
Long Term Debt And Capital Lease Obligations [Line Items]
Redemption price percentage	103.00%
2018
Long Term Debt And Capital Lease Obligations [Line Items]
Redemption price percentage	102.00%
2019
Long Term Debt And Capital Lease Obligations [Line Items]
Redemption price percentage	101.00%
2020 And Thereafter
Long Term Debt And Capital Lease Obligations [Line Items]
Redemption price percentage	100.00%