Capital Stock - Schedule of Unamortized Value of Restricted Stock (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Amortization Expense [Line Items]
Total unamortized value	$ 848	$ 1,200
2nd quarter 2015 [Member]
Amortization Expense [Line Items]
Total unamortized value	130
3rd quarter 2015 [Member]
Amortization Expense [Line Items]
Total unamortized value	130
4th quarter 2015 [Member]
Amortization Expense [Line Items]
Total unamortized value	130
1st quarter 2016 [Member]
Amortization Expense [Line Items]
Total unamortized value	125
2nd quarter 2016 [Member]
Amortization Expense [Line Items]
Total unamortized value	92
3rd quarter 2016 [Member]
Amortization Expense [Line Items]
Total unamortized value	92
4th quarter 2016 [Member]
Amortization Expense [Line Items]
Total unamortized value	92
1st quarter 2017 [Member]
Amortization Expense [Line Items]
Total unamortized value	$ 57