Restaurant Closures and Impairment of Long-Lived Assets (Narrative) (Details) $ / shares in Units, $ in Thousands		3 Months Ended	6 Months Ended
	Jul. 26, 2018 USD ($) item	Jun. 30, 2018 USD ($) item $ / shares	Jun. 30, 2018 USD ($) item $ / shares
Impairment of Long-Lived Assets Held-for-use		$ 25,166	$ 25,166
Impairment of Long-Lived Assets Held-for-use, Net		$ 18,507	$ 18,507
Impairment effect on earnings per share basic, after tax | $ / shares		$ 0.67
Impairment effect on earnings per share diluted, after tax | $ / shares		$ 0.66
Impairment effect on earnings per share basic and diluted, after tax | $ / shares			$ 0.66
Lease liability for underperformance		$ 716	$ 716
Minimum [Member]
Number Of Underperforming Stores | item			55
Maximum [Member]
Number Of Underperforming Stores | item			65
Subsequent Event [Member] | Minimum [Member]
Loss on lease termination costs	$ 8,000
Accelerated depreciation	7,000
Subsequent Event [Member] | Maximum [Member]
Loss on lease termination costs	17,000
Accelerated depreciation	$ 8,000
Chipotle [Member]
Number of restaurants closed | item		1
Chipotle [Member] | Subsequent Event [Member]
Number of restaurants closed | item	29
Pizzeria Locale [Member]
Number of restaurants closed | item		5