Long-Term Debt (Details Textual) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012		Jun. 30, 2013		Dec. 31, 2012
Debt Instrument [Line Items]
Short-term Debt	$ 700,000			$ 700,000		$ 8,700,000
Principal payments on outstanding borrowings				7,300,000
Current maturities of long-term debt	24,338,000			24,338,000		31,358,000
3.00% Convertible Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Assessment Period For Fair Value	10 years
Debt interest rate						3.00%
Debt Instrument, Interest Rate, Effective Percentage	8.25%			8.25%
Minimum trading days for conversion price	20 days
Maximum trading days for conversion price under redemption condition	30 days
Initial conversion price per share	$ 48.72
Number of business days after trading day period	5 days
Number of trading days as observation period for determined weighted price of company's common stock	10 days
Principal amount of note to be considered under conversion rate	1,000			1,000
Maximum closing sale price under condition two	98.00%
Conversion value in cash	82,600,000
Number of common shares to be issued for per $ 1,000 principal amount of note	26.6822
Conversion price per share	$ 37.48			$ 37.48
Maturity date of of notes	Mar. 15, 2020
Note agreement with a third party financial institution	115,000,000			115,000,000		115,000,000
Unamortized debt issuance cost	250,000			250,000		264,000
Total interest expense excluding amortization cost		1,725,000		1,725,000
Amortization cost of the 3.00% notes, 2.25% Notes and 8.25% Notes		1,449,000	[1]	1,588,000	[1]
Convertible Debt, Fair Value Disclosures	211,000,000			211,000,000		203,500,000
3.00% Convertible Senior Notes due 2020 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Minimum percentage of conversion price to be considered to redeem all or part of the notes	130.00%
2.25% Convertible Senior Notes due 2036 [Member]
Debt Instrument [Line Items]
Assessment Period For Fair Value	10 years
Debt interest rate	2.25%			2.25%		2.25%
Debt Instrument, Interest Rate, Effective Percentage	7.50%			7.50%
Dividend threshold for adjustment to conversion price	$ 0.14
Minimum trading days for conversion price	20 days
Maximum trading days for conversion price under redemption condition	30 days
Minimum percentage of conversion price to be considered to redeem all or part of the notes	130.00%
Initial conversion price per share	$ 77.18
Number of business days after trading day period	5 days
Number of trading days as observation period for determined weighted price of company's common stock	10 days
Principal amount of note to be considered under conversion rate	1,000			1,000
Maximum closing sale price under condition two	98.00%
Conversion value in cash	15,500,000
Number of common shares to be issued for per $ 1,000 principal amount of note	16.8439
Conversion price per share	$ 59.37			$ 59.37
Note agreement with a third party financial institution	182,753,000			182,753,000		182,753,000
Unamortized debt issuance cost	40,000			40,000		45,000
Total interest expense excluding amortization cost		2,056,000		2,056,000
Amortization cost of the 3.00% notes, 2.25% Notes and 8.25% Notes		3,404,000	[2]	3,689,000	[2]
Convertible Debt, Fair Value Disclosures	220,100,000			220,100,000		214,600,000
Two Point Two Five Percent Warrants [Member]
Debt Instrument [Line Items]
Debt interest rate	2.25%			2.25%
Three Point Zero Zero Percent Notes [Member]
Debt Instrument [Line Items]
Debt interest rate	3.00%			3.00%
2.25% Purchased Options [Member]
Debt Instrument [Line Items]
Debt interest rate	2.25%			2.25%
Maximum number of shares of common stock required to be issued under warrants	3,100,000
2.25% Warrants [Member]
Debt Instrument [Line Items]
Exercise price per common stock under warrants	80.23			80.23
3.00% Warrants [Member]
Debt Instrument [Line Items]
Debt interest rate	3.00%			3.00%
Exercise price per common stock under warrants	55.07			55.07
3.00% Purchased Options [Member]
Debt Instrument [Line Items]
Debt interest rate	3.00%			3.00%
Maximum number of shares of common stock required to be issued under warrants	3,100,000
Real Estate Related Debt [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	800,000			800,000
Interest on real estate notes, minimum	3.67%
Interest on real estate notes, maximum	9.00%
Amortization schedule	20 years
Real Estate Related Debt [Member] | Minimum [Member]
Debt Instrument [Line Items]
Variable Interest Rate	2.25%			2.25%
Real Estate Related Debt [Member] | Maximum [Member]
Debt Instrument [Line Items]
Variable Interest Rate	3.35%			3.35%
Real Estate Related Debt [Member] | Toyota Motor Credit Corporation [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	5,400,000			5,400,000
Maturity dates of long term debt	three to seven years
Amortization schedule	20 years
Total borrowings	47,200,000			47,200,000
Number of loans as per loan agreements	7
Real Estate Related Debt [Member] | Mercedes-Benz Financial Services [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	1,700,000			1,700,000
Maturity dates of long term debt	5 years
Total borrowings	46,300,000			46,300,000
Number of loans as per loan agreements	3
Real Estate Related Debt [Member] | BMW Financial Services [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	3,800,000			3,800,000
Maturity dates of long term debt	7 years
Amortization schedule	15 years
Total borrowings	67,600,000			67,600,000
Number of loans as per loan agreements	13
Foreign Note [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	2,300,000			2,300,000
Total borrowings	16,300,000			16,300,000
Third-party financial institution [Member]
Debt Instrument [Line Items]
Term loans provided under credit facility	59,400,000			59,400,000
Current maturities of long-term debt	3,000,000			3,000,000
Total borrowings	53,100,000			53,100,000
Number of loans as per loan agreements	11
Third-party financial institution [Member] | Ford Motor Credit [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	200,000			200,000
Total borrowings	5,500,000			5,500,000
Number of loans as per loan agreements	1
Mortgage Facility, Real Estate Related Debt and Acquisition Line [Member]
Debt Instrument [Line Items]
Term loans provided under credit facility	60,700,000			60,700,000
Amount available to be expanded	83,400,000			83,400,000
Unamortized debt issuance cost	500,000			500,000
Interest rate under condition second	1.45%
Interest rate under sub-condition three of condition second	1.05%
Percentage of principal payments to make its quarterly payment	1.25%
Starting date of installments to be repaid	Dec. 29, 2015
Ending date of installments to be repaid	Feb. 27, 2017
Borrowings under amended and restated mortgage facility	0
Current maturities of long-term debt	2,700,000			2,700,000
Total borrowings	$ 49,400,000			$ 49,400,000
London Interbank Offered Rate (LIBOR) [Member] | Mortgage Facility, Real Estate Related Debt and Acquisition Line [Member]
Debt Instrument [Line Items]
Variable Interest Rate	2.50%			2.50%
Federal Funds Rate [Member] | Mortgage Facility, Real Estate Related Debt and Acquisition Line [Member]
Debt Instrument [Line Items]
Variable Interest Rate	0.50%			0.50%

[1] Represents the incremental impact of the accounting for convertible debt as primarily codified in ASC 470, Debt

[2] Represents the incremental impact of the accounting for convertible debt as primarily codified in ASC 470, Debt.