Hedging Transactions and Derivative Financial Instruments - Summary of Reconciliation of Company's Derivatives by Contract Type (Parenthetical) (Detail) $ in Millions	Dec. 31, 2016 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Aggregate margin account balances included in cash and cash equivalents	$ 9.2

Aggregate margin account balances included in cash and cash equivalents.

No definition available.

Name:	cot_AggregateMarginAccountBalancesIncludedInCashAndCashEquivalents
Namespace Prefix:	cot_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant