Acquisitions and Dispositions - KCWI - Additional Information (Details) - USD ($)			3 Months Ended								10 Months Ended	12 Months Ended
	Mar. 14, 2016	Oct. 24, 2014	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Revenue included in consolidated statements of operations and comprehensive income			$ 653,664,000	$ 611,870,000	$ 626,115,000	$ 540,317,000	$ 309,879,000	$ 275,659,000	$ 261,994,000	$ 255,658,000		$ 2,431,966,000	$ 1,103,190,000	$ 896,377,000
Operating income (loss)			$ 140,837,000	$ 129,072,000	$ 138,685,000	$ 110,151,000	$ 92,475,000	$ 72,897,000	$ 64,007,000	$ 57,929,000		$ 518,745,000	287,308,000	$ 206,107,000
KCWI [Member]
Business Acquisition [Line Items]
Purchase price of entities to be acquired	$ 3,900,000
Deposits and payments for acquisitions		$ 200,000
Acquisition related costs													$ 0
Acquisition date	Mar. 14, 2016
Revenue included in consolidated statements of operations and comprehensive income											$ 3,100,000
Operating income (loss)											$ 2,700,000