Debt (Interest Rates) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 $150 Million Senior Secured Credit Facility [Member]	Dec. 31, 2013 Term Loan Due March 2015 [Member] Korea Subsidiaries [Member]	Dec. 31, 2012 Term Loan Due March 2015 [Member] Korea Subsidiaries [Member]	Mar. 31, 2012 Term Loan Due March 2015 [Member] Korea Subsidiaries [Member]	Dec. 31, 2013 Term Loan Due June 2016 [Member] Korea Subsidiaries [Member]	Apr. 30, 2013 Term Loan Due June 2016 [Member] Korea Subsidiaries [Member]	Dec. 31, 2012 Term Loan Due June 2016 [Member] Korea Subsidiaries [Member]	Dec. 31, 2013 Term Loan Due July 2017 [Member] Tranche A [Member] Korea Subsidiaries [Member]	Dec. 31, 2012 Term Loan Due July 2017 [Member] Tranche A [Member] Korea Subsidiaries [Member]	Dec. 31, 2013 Term Loan Due July 2017 [Member] Tranche B [Member] Korea Subsidiaries [Member]	Dec. 31, 2012 Term Loan Due July 2017 [Member] Tranche B [Member] Korea Subsidiaries [Member]	Dec. 31, 2013 Term Loan Due September 2017 [Member] Korea Subsidiaries [Member]	Mar. 31, 2013 Term Loan Due September 2017 [Member] Korea Subsidiaries [Member]	Dec. 31, 2012 Term Loan Due September 2017 [Member] Korea Subsidiaries [Member]	Dec. 31, 2013 Term Loan Due December 2019 [Member] Korea Subsidiaries [Member]	Dec. 31, 2012 Term Loan Due December 2019 [Member] Korea Subsidiaries [Member]	Nov. 30, 2012 Term Loan Due December 2019 [Member] Korea Subsidiaries [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate at Period End				4.29%	4.21%		3.95%		0.00%	4.14%	4.26%	4.18%	4.26%	3.76%		0.00%	3.95%	4.01%
Long-term Debt, Gross	$ 1,646,350,000	$ 1,545,000,000
Percent of fixed rate debt	80.60%	83.80%
Percent of variable rate debt	19.40%	16.20%
Interest rate				2.30%			3.70%	3.80%						1.75%			3.70%
Credit facility, borrowing capacity			$ 150,000,000.0			$ 100,000,000		$ 150,000,000.0							$ 150,000,000.0				$ 100,000,000.0