Information about Domestic and International Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from External Customers	$ 20,194	$ 20,009	$ 25,152	$ 36,138	$ 24,495	$ 21,790	$ 24,416	$ 32,282	$ 101,493	$ 102,983	$ 99,825
Net Assets	19,797				26,265				19,797	26,265
Property and Equipment	6,380				10,637				6,380	10,637
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from External Customers									101,493	102,983	99,825
Net Assets	15,143				21,766				15,143	21,766
Property and Equipment	6,380				10,637				6,380	10,637
CANADA
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	$ 4,654				$ 4,499				$ 4,654	$ 4,499