Subsequent Events (Details)	Mar. 15, 2018 $ / shares	Feb. 21, 2018 USD ($) Companies	Feb. 01, 2018	Jan. 04, 2018 USD ($)	Jan. 02, 2018 USD ($)	Nov. 03, 2017 USD ($)
Subsequent Event
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Cash Paid | $ / shares	$ 0.075
Transcorp [Member] | Subsequent Event
Subsequent Event [Line Items]
Fair Value of Business Combination				$ 7,400,000
Secured Syndicated Credit Facility, Fifth Amendment [Member] | Regions Bank | Secured Term Loan [Member]
Subsequent Event [Line Items]
Line of Credit, Accordion						$ 175,000,000
Secured Syndicated Credit Facility, Fifth Amendment [Member] | Regions Bank | Revolving Credit Facility | Subsequent Event
Subsequent Event [Line Items]
Credit agreement, maximum borrowing capacity		$ 450,000,000
Secured Syndicated Credit Facility, Sixth Amendment [Member] | Regions Bank | Subsequent Event
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity		$ 650,000,000
Number of Participating Banks | Companies		10
Secured Syndicated Credit Facility, Sixth Amendment [Member] | Regions Bank | Secured Term Loan [Member] | Subsequent Event
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity		$ 250,000,000
Line of Credit Facility, Term		5 years
Secured Syndicated Credit Facility, Sixth Amendment [Member] | Regions Bank | Revolving Credit Facility | Subsequent Event
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity		$ 400,000,000
Line of Credit Facility, Term		5 years
Maximum [Member] | Secured Syndicated Credit Facility, Fifth Amendment [Member] | Regions Bank | Secured Term Loan [Member]
Subsequent Event [Line Items]
Line of Credit, Accordion						$ 100,000,000
Maximum [Member] | Secured Syndicated Credit Facility, Sixth Amendment [Member] | Regions Bank | Secured Term Loan [Member] | Subsequent Event
Subsequent Event [Line Items]
Line of Credit, Accordion		$ 150,000,000
PML JV [Member] | Subsequent Event
Subsequent Event [Line Items]
Percentage of Equity Interest in Joint Venture by Other Party, Irrevocable option to reacquire					10.00%
Percentage of Membership Interest in Joint Venture by Other Party			10.00%
Proceeds from Noncontrolling Interests					$ 5,000,000