Financial Instruments and Fair Value Measurements - Additional information (Details) (USD $)	12 Months Ended	3 Months Ended
	Dec. 31, 2008	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2007
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long term debt		66,487,000	$ 63,804,000
Retained interest promissory note receivable	15,200,000	20,000,000
Notes, maturity period	15 years
Carrying Value | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Retained Interest, Fair Value Disclosure		9,974,000	9,932,000
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Note maturity year	2022
Retained interest, effective interest rate		3.70%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Note maturity year	2024
Retained interest, effective interest rate		11.60%
Defeased Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long term debt				$ 29,300,000