Debt (Details Textual) (USD $)	1 Months Ended	12 Months Ended							1 Months Ended											0 Months Ended	1 Months Ended	0 Months Ended	12 Months Ended		0 Months Ended		12 Months Ended				12 Months Ended
	Jul. 26, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Aug. 15, 2011	Dec. 31, 2013 7.625% senior notes, due 2019	Dec. 31, 2012 7.625% senior notes, due 2019	Jul. 26, 2011 7.625% senior notes, due 2019	Jul. 26, 2011 Term loans, bearing interest at variable rates, due 2018, net of original issue	Dec. 31, 2013 Term loans, bearing interest at variable rates, due 2018, net of original issue		Dec. 31, 2012 Term loans, bearing interest at variable rates, due 2018, net of original issue		Dec. 15, 2011 Term loans, bearing interest at variable rates, due 2018, net of original issue	Dec. 31, 2013 Partnership notes, due 2020	Dec. 31, 2012 Partnership notes, due 2020	Dec. 31, 2013 Incremental Credit Facility	Jul. 26, 2011 Incremental Credit Facility	Dec. 31, 2013 Revolving Credit Facility	Jan. 24, 2013 IPO Term loans, bearing interest at variable rates, due 2018, net of original issue	Jan. 31, 2013 IPO Term loans, bearing interest at variable rates, due 2018, net of original issue	Jan. 24, 2013 IPO Partnership notes, due 2020	Dec. 31, 2013 IPO Partnership notes, due 2020	Jan. 23, 2013 IPO Partnership notes, due 2020	Aug. 28, 2013 IPO Revolving Credit Facility with A Term Extending through January 2018	Jan. 24, 2013 IPO Revolving Credit Facility with A Term Extending through January 2018	Dec. 31, 2013 IPO Revolving Credit Facility with A Term Extending through January 2018	Dec. 31, 2012 IPO Revolving Credit Facility with A Term Extending through January 2018	Sep. 30, 2013 IPO Revolving Credit Facility with A Term Extending through January 2018	Aug. 28, 2013 IPO Uncommitted Incremental Revolving Credit Facility	Dec. 31, 2013 Credit Agreement Revolving Credit Facility
Debt (Textual) [Abstract]
Period for term loan (in years)									7 years																						5 years
Long-term Debt		$ 689,100,000	$ 723,400,000			$ 400,000,000	$ 400,000,000		$ 300,000,000	$ 99,100,000	[1]	$ 323,400,000	[1]		$ 150,000,000	$ 0
Principal amount of term loan																									150,000,000.0	100,000,000.0					150,000,000
Percent of principal amount repayable for term loan on quarterly basis (as a percent)	1.00%
Debt discount									2,100,000
Incremental Credit Facilities, Remaining Borrowing Capacity																	45,000,000
Long-term Debt, Gross																			100,100,000
Incremental facilities under credit agreement																		75,000,000.0												100,000,000.0
Borrowed term loan														30,000,000.0
Remaining letters of credit agreement amount																											109,300,000				147,900,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage																											0.40%				0.35%
Letters of credit outstanding under revolving facility																											700,000				2,100,000
Debt issuance cost		19,100,000																			700,000				900,000	2,200,000
Repayments of long-term debt		225,000,000	3,300,000	1,600,000																225,000,000.0
Unamortized debt issuance expense																				2,900,000				3,700,000
Debt Issuance Cost Immediately Expensed																							800,000
Senior notes								400,000,000																150,000,000.0
Borrowings under the term Loan bear interest, option (as a percent)		1.00%
Interest rate (as a percent)						7.625%	7.625%	7.625%							7.375%	7.375%								7.375%
Redeem partnership note percentage (as a percent)																						35.00%
Applicable margin for base rate loan (as a percent)		2.00%
Borrowings under the term loan bear interest, in case of LIBOR Loan (as a percent)		3.00%
The weighted-average interest rate for borrowings outstanding under credit agreement (as a percent)																			4.07%
Amount outstanding under term loan and incremental facilities																													40,000,000.0
Debt Instrument, Interest Rate, Effective Percentage																											2.43%
Debt issuance costs		6,900,000	0	19,100,000																								600,000
Maturity year	2019
Percentage of redemption of the notes using proceeds of certain equity offerings (as a percent)		35.00%
Redemption of notes as percentage of principal amount change of control event (as a percent)		101.00%
Redemption of notes as percentage of principal amount asset disposition (as percent)		100.00%
Long-term Debt, Maturities, 2014		1,000,000
Long-term Debt, Maturities, 2015		1,000,000
Long-term Debt, Maturities, 2016		1,000,000
Long-term Debt, Maturities, 2017		1,000,000
Long-term Debt, Maturities, 2018		96,000,000
Aggregate notional amount for interest rate swap agreements					$ 125,000,000

[1] Borrowed under the Company’s Credit Agreement dated as of July 26, 2011 (“Credit Agreement”).